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Theorem pm2.46 728
Description: Theorem *2.46 of [WhiteheadRussell] p. 106. (Contributed by NM, 3-Jan-2005.)
Assertion
Ref Expression
pm2.46 (¬ (𝜑𝜓) → ¬ 𝜓)

Proof of Theorem pm2.46
StepHypRef Expression
1 olc 700 . 2 (𝜓 → (𝜑𝜓))
21con3i 621 1 (¬ (𝜑𝜓) → ¬ 𝜓)
Colors of variables: wff set class
Syntax hints:  ¬ wn 3  wi 4  wo 697
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-ia1 105  ax-ia2 106  ax-in1 603  ax-in2 604  ax-io 698
This theorem depends on definitions:  df-bi 116
This theorem is referenced by:  pm2.48  730  pm2.49  731  ioran  741  eueq3dc  2858  regexmidlem1  4448
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