Theorem anabss1

Description: Absorption of antecedent into conjunction. (Contributed by NM, 20-Jul-1996) (Proof shortened by Wolf Lammen, 31-Dec-2012)

	Ref	Expression
Hypothesis	anabss1.1	|- ( ( ( ph /\ ps ) /\ ph ) -> ch )
Assertion	anabss1	|- ( ( ph /\ ps ) -> ch )

Proof

Step	Hyp	Ref	Expression
1		anabss1.1	|- ( ( ( ph /\ ps ) /\ ph ) -> ch )
2	1	an32s	|- ( ( ( ph /\ ph ) /\ ps ) -> ch )
3	2	anabsan	|- ( ( ph /\ ps ) -> ch )