Theorem an13s

Description: Swap two conjuncts in antecedent. (Contributed by NM, 31-May-2006)

	Ref	Expression
Hypothesis	an12s.1	|- ( ( ph /\ ( ps /\ ch ) ) -> th )
Assertion	an13s	|- ( ( ch /\ ( ps /\ ph ) ) -> th )

Proof

Step	Hyp	Ref	Expression
1		an12s.1	|- ( ( ph /\ ( ps /\ ch ) ) -> th )
2	1	exp32	|- ( ph -> ( ps -> ( ch -> th ) ) )
3	2	com13	|- ( ch -> ( ps -> ( ph -> th ) ) )
4	3	imp32	|- ( ( ch /\ ( ps /\ ph ) ) -> th )