Theorem conax1

Description: Contrapositive of ax-1 . (Contributed by BJ, 28-Oct-2023)

	Ref	Expression
Assertion	conax1	|- ( -. ( ph -> ps ) -> -. ps )

Proof

Step	Hyp	Ref	Expression
1		ax-1	|- ( ps -> ( ph -> ps ) )
2	1	con3i	|- ( -. ( ph -> ps ) -> -. ps )