Theorem anabsan2

Description: Absorption of antecedent with conjunction. (Contributed by NM, 10-May-2004)

	Ref	Expression
Hypothesis	anabsan2.1	|- ( ( ph /\ ( ps /\ ps ) ) -> ch )
Assertion	anabsan2	|- ( ( ph /\ ps ) -> ch )

Proof

Step	Hyp	Ref	Expression
1		anabsan2.1	|- ( ( ph /\ ( ps /\ ps ) ) -> ch )
2	1	an12s	|- ( ( ps /\ ( ph /\ ps ) ) -> ch )
3	2	anabss7	|- ( ( ph /\ ps ) -> ch )