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Theorem notnoti 115

Description: Infer double negation. (Contributed by NM, 27-Feb-2008.)

Hypothesis

Ref	Expression
negbi.1

Assertion

Ref	Expression
notnoti

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Proof of Theorem notnoti

Step	Hyp	Ref	Expression
1		negbi.1	. 2
2		notnot1 114	. 2
3	1, 2	ax-mp 8	1

Colors of variables: wff setvar class

Syntax hints:   wn 3

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

This theorem is referenced by:  nbn3  337  fal  1322  19.2OLD  1700  ax9dgen  1716  eqtfinrelk  4486  2p1e3c  6156

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