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Theorem pm2.01da 457
Description: Deduction based on reductio ad absurdum. (Contributed by Mario Carneiro, 9-Feb-2017.)
Hypothesis
Ref Expression
pm2.01da.1 ((𝜑𝜓) → ¬ 𝜓)
Assertion
Ref Expression
pm2.01da (𝜑 → ¬ 𝜓)

Proof of Theorem pm2.01da
StepHypRef Expression
1 pm2.01da.1 . . 3 ((𝜑𝜓) → ¬ 𝜓)
21ex 449 . 2 (𝜑 → (𝜓 → ¬ 𝜓))
32pm2.01d 180 1 (𝜑 → ¬ 𝜓)
Colors of variables: wff setvar class
Syntax hints:  ¬ wn 3  wi 4  wa 383
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 196  df-an 385
This theorem is referenced by:  efrirr  5019  omlimcl  7545  hartogslem1  8330  cfslb2n  8973  fin23lem41  9057  tskuni  9484  4sqlem18  15504  ramlb  15561  ivthlem2  23028  ivthlem3  23029  cosne0  24080  footne  25415  unbdqndv1  31669  unbdqndv2  31672  knoppndv  31695  fmtno4prm  40025
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