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Metamath Proof Explorer

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 )