Theorem pm2.43a

Description: Inference absorbing redundant antecedent. (Contributed by NM, 7-Nov-1995) (Proof shortened by Mel L. O'Cat, 28-Nov-2008)

	Ref	Expression
Hypothesis	pm2.43a.1	|- ( ps -> ( ph -> ( ps -> ch ) ) )
Assertion	pm2.43a	|- ( ps -> ( ph -> ch ) )

Proof

Step	Hyp	Ref	Expression
1		pm2.43a.1	|- ( ps -> ( ph -> ( ps -> ch ) ) )
2		id	|- ( ps -> ps )
3	2 1	mpid	|- ( ps -> ( ph -> ch ) )