Theorem notnoti 143

Description: Inference associated with notnot 142. (Contributed by NM, 27-Feb-2008.)

Hypothesis

Ref	Expression
notnoti.1	⊢ 𝜑

Assertion

Ref	Expression
notnoti	⊢ ¬ ¬ 𝜑

Proof of Theorem notnoti

Step	Hyp	Ref	Expression
1		notnoti.1	. 2 ⊢ 𝜑
2		notnot 142	. 2 ⊢ (𝜑 → ¬ ¬ 𝜑)
3	1, 2	ax-mp 5	1 ⊢ ¬ ¬ 𝜑

Syntax hints:  ¬ wn 3

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8

This theorem is referenced by:  nbn3  372  fal  1548  ax6dgen  2117  dfnul2  4328  dfnul2OLD  4330  dfnul4OLD  4332  mdegleb  26091  nexntru  36116  bj-ntrufal  36273  ifpdfan2  43130  aisbnaxb  46526