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Theorem exmidd 405
Description: Law of excluded middle in a context. (Contributed by Mario Carneiro, 9-Feb-2017.)
Assertion
Ref Expression
exmidd (φ → (ψ ¬ ψ))

Proof of Theorem exmidd
StepHypRef Expression
1 exmid 404 . 2 (ψ ¬ ψ)
21a1i 10 1 (φ → (ψ ¬ 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)
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