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Theorem conax1 643
Description: Contrapositive of ax-1 6. (Contributed by BJ, 28-Oct-2023.)
Assertion
Ref Expression
conax1  |-  ( -.  ( ph  ->  ps )  ->  -.  ps )

Proof of Theorem conax1
StepHypRef Expression
1 ax-1 6 . 2  |-  ( ps 
->  ( ph  ->  ps ) )
21con3i 622 1  |-  ( -.  ( ph  ->  ps )  ->  -.  ps )
Colors of variables: wff set class
Syntax hints:   -. wn 3    -> wi 4
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-in1 604  ax-in2 605
This theorem is referenced by:  conax1k  644
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