ILE Home Intuitionistic Logic Explorer < Previous   Next >
Nearby theorems
Mirrors  >  Home  >  ILE Home  >  Th. List  >  notnotd GIF version

Theorem notnotd 619
Description: Deduction associated with notnot 618 and notnoti 634. (Contributed by Jarvin Udandy, 2-Sep-2016.) Avoid biconditional. (Revised by Wolf Lammen, 27-Mar-2021.)
Hypothesis
Ref Expression
notnotd.1 (𝜑𝜓)
Assertion
Ref Expression
notnotd (𝜑 → ¬ ¬ 𝜓)

Proof of Theorem notnotd
StepHypRef Expression
1 notnotd.1 . 2 (𝜑𝜓)
2 notnot 618 . 2 (𝜓 → ¬ ¬ 𝜓)
31, 2syl 14 1 (𝜑 → ¬ ¬ 𝜓)
Colors of variables: wff set class
Syntax hints:  ¬ wn 3  wi 4
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-in1 603  ax-in2 604
This theorem is referenced by:  ismkvnex  7029  exmidonfinlem  7049  mod2eq1n2dvds  11583
  Copyright terms: Public domain W3C validator