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Theorem pm2.85 826
Description: Theorem *2.85 of [WhiteheadRussell] p. 108. (Contributed by NM, 3-Jan-2005.) (Proof shortened by Wolf Lammen, 5-Jan-2013.)
Assertion
Ref Expression
pm2.85 (((φ ψ) → (φ χ)) → (φ (ψχ)))

Proof of Theorem pm2.85
StepHypRef Expression
1 orimdi 820 . 2 ((φ (ψχ)) ↔ ((φ ψ) → (φ χ)))
21biimpri 197 1 (((φ ψ) → (φ χ)) → (φ (ψχ)))
Colors of variables: wff setvar class
Syntax hints:  wi 4   wo 357
This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-3 7  ax-mp 8
This theorem depends on definitions:  df-bi 177  df-or 359
This theorem is referenced by: (None)
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