Theorem notnoti 144

Description: Inference associated with notnot 143. (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 143	. 2 ⊢ (𝜑 → ¬ ¬ 𝜑)
3	1, 2	ax-mp 5	1 ⊢ ¬ ¬ 𝜑

This proof depends on syntax axioms:  ¬ wn 3

This proof depends on axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8

This theorem is used by:  nbn3  376  fal  1584  ax6dgen  2166  dfnul2  4289  nrelv  5788  mdegleb  26274  nexntru  36974  bj-ntrufal  37221  ifpdfan2  44249  rext0  45707  aisbnaxb  47708