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Theorem inegd 1335
Description: Negation introduction rule from natural deduction. (Contributed by Mario Carneiro, 9-Feb-2017.)
Hypothesis
Ref Expression
inegd.1 ((𝜑𝜓) → ⊥)
Assertion
Ref Expression
inegd (𝜑 → ¬ 𝜓)

Proof of Theorem inegd
StepHypRef Expression
1 inegd.1 . . 3 ((𝜑𝜓) → ⊥)
21ex 114 . 2 (𝜑 → (𝜓 → ⊥))
3 dfnot 1334 . 2 𝜓 ↔ (𝜓 → ⊥))
42, 3sylibr 133 1 (𝜑 → ¬ 𝜓)
Colors of variables: wff set class
Syntax hints:  ¬ wn 3  wi 4  wa 103  wfal 1321
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-ia1 105  ax-ia2 106  ax-ia3 107  ax-in1 588  ax-in2 589
This theorem depends on definitions:  df-bi 116  df-tru 1319  df-fal 1322
This theorem is referenced by:  genpdisj  7299  cauappcvgprlemdisj  7427  caucvgprlemdisj  7450  caucvgprprlemdisj  7478  suplocexprlemdisj  7496  suplocexprlemub  7499  suplocsrlem  7584  resqrexlemgt0  10760  resqrexlemoverl  10761  leabs  10814  climge0  11062  ennnfonelemex  11854  dedekindeu  12697  dedekindicclemicc  12706
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