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Theorem conax1 625
Description: Contrapositive of ax-1 6. (Contributed by BJ, 28-Oct-2023.)
Assertion
Ref Expression
conax1 (¬ (𝜑𝜓) → ¬ 𝜓)

Proof of Theorem conax1
StepHypRef Expression
1 ax-1 6 . 2 (𝜓 → (𝜑𝜓))
21con3i 604 1 (¬ (𝜑𝜓) → ¬ 𝜓)
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 586  ax-in2 587
This theorem is referenced by:  conax1k  626
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