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Theorem con2bii2 34496
Description: A contraposition inference. (Contributed by ML, 18-Oct-2020.)
Hypothesis
Ref Expression
con2bii2.1 (𝜑 ↔ ¬ 𝜓)
Assertion
Ref Expression
con2bii2 𝜑𝜓)

Proof of Theorem con2bii2
StepHypRef Expression
1 con2bii2.1 . . 3 (𝜑 ↔ ¬ 𝜓)
21con2bii 359 . 2 (𝜓 ↔ ¬ 𝜑)
32bicomi 225 1 𝜑𝜓)
Colors of variables: wff setvar class
Syntax hints:  ¬ wn 3  wb 207
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8
This theorem depends on definitions:  df-bi 208
This theorem is referenced by:  fvineqsneq  34575
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