Theorem bj-con4iALT 32547

Description: Alternate proof of con4i 113. Probably the original proof. (Contributed by BJ, 29-Mar-2020.) (New usage is discouraged.) (Proof modification is discouraged.)

Hypothesis

Ref	Expression
bj-con4iALT.1	|- ( -. ph -> -. ps )

Assertion

Ref	Expression
bj-con4iALT	|- ( ps -> ph )

Proof of Theorem bj-con4iALT

Step	Hyp	Ref	Expression
1		bj-con4iALT.1	. 2 |- ( -. ph -> -. ps )
2		con4 112	. 2 |- ( ( -. ph -> -. ps ) -> ( ps -> ph ) )
3	1, 2	ax-mp 5	1 |- ( ps -> ph )

Syntax hints:   -. wn 3   -> wi 4

This theorem was proved from axioms:  ax-mp 5  ax-3 8

This theorem is referenced by: (None)