Theorem mp1i 11

Description: Drop and replace an antecedent. (Contributed by Stefan O'Rear, 29-Jan-2015.)

Hypotheses

Ref	Expression
mp1i.a	|- ph
mp1i.b	|- (ph -> ps)

Assertion

Ref	Expression
mp1i	|- (ch -> ps)

Proof of Theorem mp1i

Step	Hyp	Ref	Expression
1		mp1i.a	. . 3 |- ph
2		mp1i.b	. . 3 |- (ph -> ps)
3	1, 2	ax-mp 5	. 2 |- ps
4	3	a1i 10	1 |- (ch -> ps)

Syntax hints:   -> wi 4

This theorem was proved from axioms:  ax-mp 5  ax-1 6

This theorem is referenced by: (None)