Theorem mp2

Description: A double modus ponens inference. (Contributed by NM, 5-Apr-1994)

	Ref	Expression
Hypotheses	mp2.1	|- ph
	mp2.2	|- ps
	mp2.3	|- ( ph -> ( ps -> ch ) )
Assertion	mp2	|- ch

Proof

Step	Hyp	Ref	Expression
1		mp2.1	|- ph
2		mp2.2	|- ps
3		mp2.3	|- ( ph -> ( ps -> ch ) )
4	1 3	ax-mp	|- ( ps -> ch )
5	2 4	ax-mp	|- ch