Theorem anabsan

Description: Absorption of antecedent with conjunction. (Contributed by NM, 24-Mar-1996)

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

Proof

Step	Hyp	Ref	Expression
1		anabsan.1	|- ( ( ( ph /\ ph ) /\ ps ) -> ch )
2		pm4.24	|- ( ph <-> ( ph /\ ph ) )
3	2 1	sylanb	|- ( ( ph /\ ps ) -> ch )