NFE Home New Foundations Explorer < Previous   Next >
Nearby theorems
Mirrors  >  Home  >  NFE Home  >  Th. List  >  pm2.48 GIF version

Theorem pm2.48 389
Description: Theorem *2.48 of [WhiteheadRussell] p. 107. (Contributed by NM, 3-Jan-2005.)
Assertion
Ref Expression
pm2.48 (¬ (φ ψ) → (φ ¬ ψ))

Proof of Theorem pm2.48
StepHypRef Expression
1 pm2.46 387 . 2 (¬ (φ ψ) → ¬ ψ)
21olcd 382 1 (¬ (φ ψ) → (φ ¬ ψ))
Colors of variables: wff setvar class
Syntax hints:  ¬ wn 3  wi 4   wo 357
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
This theorem is referenced by: (None)
  Copyright terms: Public domain W3C validator