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Theorem bibi1i 221
Description: Inference adding a biconditional to the right in an equivalence. (Contributed by NM, 5-Aug-1993.)
Hypothesis
Ref Expression
bibi.a (𝜑𝜓)
Assertion
Ref Expression
bibi1i ((𝜑𝜒) ↔ (𝜓𝜒))

Proof of Theorem bibi1i
StepHypRef Expression
1 bicom 132 . 2 ((𝜑𝜒) ↔ (𝜒𝜑))
2 bibi.a . . 3 (𝜑𝜓)
32bibi2i 220 . 2 ((𝜒𝜑) ↔ (𝜒𝜓))
4 bicom 132 . 2 ((𝜒𝜓) ↔ (𝜓𝜒))
51, 3, 43bitri 199 1 ((𝜑𝜒) ↔ (𝜓𝜒))
Colors of variables: wff set class
Syntax hints:  wb 102
This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-mp 7  ax-ia1 103  ax-ia2 104  ax-ia3 105
This theorem depends on definitions:  df-bi 114
This theorem is referenced by:  bibi12i  222  bilukdc  1303  sbrbis  1851  necon1abiddc  2282  necon1bbiddc  2283  necon4abiddc  2293  elrab3t  2720  ssequn1  3141  asymref  4738
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