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Theorem pm4.83 895
Description: Theorem *4.83 of [WhiteheadRussell] p. 122. (Contributed by NM, 3-Jan-2005.)
Assertion
Ref Expression
pm4.83 (((φψ) φψ)) ↔ ψ)

Proof of Theorem pm4.83
StepHypRef Expression
1 exmid 404 . . 3 (φ ¬ φ)
21a1bi 327 . 2 (ψ ↔ ((φ ¬ φ) → ψ))
3 jaob 758 . 2 (((φ ¬ φ) → ψ) ↔ ((φψ) φψ)))
42, 3bitr2i 241 1 (((φψ) φψ)) ↔ ψ)
Colors of variables: wff setvar class
Syntax hints:  ¬ wn 3  wi 4  wb 176   wo 357   wa 358
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 177  df-or 359  df-an 360
This theorem is referenced by: (None)
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