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Theorem bj-biorfi 32905
Description: This should be labeled "biorfi" while the current biorfi 953 should be labeled "biorfri". The dual of biorf 951 is not biantr 831 but iba 519 (and ibar 520). So there should also be a "biorfr". (Note that these four statements can actually be strengthened to biconditionals.) (Contributed by BJ, 26-Oct-2019.) (Proof modification is discouraged.)
Hypothesis
Ref Expression
bj-biorfi.1 ¬ 𝜑
Assertion
Ref Expression
bj-biorfi (𝜓 ↔ (𝜑𝜓))

Proof of Theorem bj-biorfi
StepHypRef Expression
1 bj-biorfi.1 . 2 ¬ 𝜑
2 biorf 951 . 2 𝜑 → (𝜓 ↔ (𝜑𝜓)))
31, 2ax-mp 5 1 (𝜓 ↔ (𝜑𝜓))
Colors of variables: wff setvar class
Syntax hints:  ¬ wn 3  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:  bj-falor  32906
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