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Metamath Proof Explorer

Theorem conax1k

Description: Weakening of conax1 . General instance of pm2.51 and of pm2.52 . (Contributed by BJ, 28-Oct-2023)

Ref Expression
Assertion conax1k 
|- ( -. ( ph -> ps ) -> ( ch -> -. ps ) )

Proof

Step Hyp Ref Expression
1 conax1 
 |-  ( -. ( ph -> ps ) -> -. ps )
2 1 a1d 
 |-  ( -. ( ph -> ps ) -> ( ch -> -. ps ) )