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Theorem bi2anan9r 539
Description: Deduction joining two equivalences to form equivalence of conjunctions. (Contributed by NM, 19-Feb-1996.)
Hypotheses
Ref Expression
bi2an9.1 (𝜑 → (𝜓𝜒))
bi2an9.2 (𝜃 → (𝜏𝜂))
Assertion
Ref Expression
bi2anan9r ((𝜃𝜑) → ((𝜓𝜏) ↔ (𝜒𝜂)))

Proof of Theorem bi2anan9r
StepHypRef Expression
1 bi2an9.1 . . 3 (𝜑 → (𝜓𝜒))
2 bi2an9.2 . . 3 (𝜃 → (𝜏𝜂))
31, 2bi2anan9 538 . 2 ((𝜑𝜃) → ((𝜓𝜏) ↔ (𝜒𝜂)))
43ancoms 255 1 ((𝜃𝜑) → ((𝜓𝜏) ↔ (𝜒𝜂)))
Colors of variables: wff set class
Syntax hints:  wi 4  wa 97  wb 98
This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-mp 7  ax-ia1 99  ax-ia2 100  ax-ia3 101
This theorem depends on definitions:  df-bi 110
This theorem is referenced by: (None)
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