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Theorem nbior 903
Description: If two propositions are not equivalent, then at least one is true. (Contributed by BJ, 19-Apr-2019.) (Proof shortened by Wolf Lammen, 19-Jan-2020.)
Assertion
Ref Expression
nbior (¬ (𝜑𝜓) → (𝜑𝜓))

Proof of Theorem nbior
StepHypRef Expression
1 norbi 902 . 2 (¬ (𝜑𝜓) → (𝜑𝜓))
21con1i 146 1 (¬ (𝜑𝜓) → (𝜑𝜓))
Colors of variables: wff setvar class
Syntax hints:  ¬ wn 3  wi 4  wb 197  wo 865
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 198  df-or 866
This theorem is referenced by:  nmogtmnf  27950  nmopgtmnf  29052
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