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Theorem pm4.39 746
Description: Theorem *4.39 of [WhiteheadRussell] p. 118. (Contributed by NM, 3-Jan-2005.)
Assertion
Ref Expression
pm4.39 (((𝜑𝜒) ∧ (𝜓𝜃)) → ((𝜑𝜓) ↔ (𝜒𝜃)))

Proof of Theorem pm4.39
StepHypRef Expression
1 simpl 106 . 2 (((𝜑𝜒) ∧ (𝜓𝜃)) → (𝜑𝜒))
2 simpr 107 . 2 (((𝜑𝜒) ∧ (𝜓𝜃)) → (𝜓𝜃))
31, 2orbi12d 717 1 (((𝜑𝜒) ∧ (𝜓𝜃)) → ((𝜑𝜓) ↔ (𝜒𝜃)))
Colors of variables: wff set class
Syntax hints:  wi 4  wa 101  wb 102  wo 639
This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-mp 7  ax-ia1 103  ax-ia2 104  ax-ia3 105  ax-io 640
This theorem depends on definitions:  df-bi 114
This theorem is referenced by: (None)
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