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Theorem pm4.71i 483
Description: Inference converting an implication to a biconditional with conjunction. Inference from Theorem *4.71 of [WhiteheadRussell] p. 120.
Hypothesis
Ref Expression
pm4.71i.1 (φψ)
Assertion
Ref Expression
pm4.71i (φ ↔ (φψ))

Proof of Theorem pm4.71i
StepHypRef Expression
1 pm4.71i.1 . 2 (φψ)
2 pm4.71 481 . 2 ((φψ) ↔ (φ ↔ (φψ)))
31, 2mpbi 164 1 (φ ↔ (φψ))
Colors of variables: wff set class
Syntax hints:   → wi 2   ↔ wb 127   ∧ wa 196
This theorem is referenced by:  2eu5 1071  imadmrn 2610  map0e 3266  xpsnen 3339  aceq5lem2 3559  infmap2lem1 4951
This theorem was proved from axioms:  ax-1 3  ax-2 4  ax-3 5  ax-mp 6
This theorem depends on definitions:  df-bi 128  df-an 198
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