Theorem simp1d

Description: Deduce a conjunct from a triple conjunction. (Contributed by NM, 4-Sep-2005)

	Ref	Expression
Hypothesis	3simp1d.1	|- ( ph -> ( ps /\ ch /\ th ) )
Assertion	simp1d	|- ( ph -> ps )

Proof

Step	Hyp	Ref	Expression
1		3simp1d.1	|- ( ph -> ( ps /\ ch /\ th ) )
2		simp1	|- ( ( ps /\ ch /\ th ) -> ps )
3	1 2	syl	|- ( ph -> ps )