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Theorem notnoti 123
Description: Infer double negation. (Contributed by NM, 27-Feb-2008.)
Hypothesis
Ref Expression
negbi.1
Assertion
Ref Expression
notnoti

Proof of Theorem notnoti
StepHypRef Expression
1 negbi.1 . 2
2 notnot1 122 . 2
31, 2ax-mp 5 1
Colors of variables: wff setvar class
Syntax hints:  -.wn 3
This theorem is referenced by:  nbn3  348  fal  1402  ax6dgen  1824  mdegleb  22464  nextnt  29870  amosym1  29891  aisbnaxb  32106
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8
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