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Theorem bj-notbid 11818
Description: Deduction form of bj-notbi 11816. (Contributed by BJ, 27-Jan-2020.) (Proof modification is discouraged.)
Hypothesis
Ref Expression
bj-notbid.1 (𝜑 → (𝜓𝜒))
Assertion
Ref Expression
bj-notbid (𝜑 → (¬ 𝜓 ↔ ¬ 𝜒))

Proof of Theorem bj-notbid
StepHypRef Expression
1 bj-notbid.1 . 2 (𝜑 → (𝜓𝜒))
2 bj-notbi 11816 . 2 ((𝜓𝜒) → (¬ 𝜓 ↔ ¬ 𝜒))
31, 2syl 14 1 (𝜑 → (¬ 𝜓 ↔ ¬ 𝜒))
Colors of variables: wff set class
Syntax hints:  ¬ wn 3  wi 4  wb 103
This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-mp 7  ax-ia1 104  ax-ia2 105  ax-ia3 106  ax-in1 579  ax-in2 580
This theorem depends on definitions:  df-bi 115
This theorem is referenced by: (None)
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