notnotnot - Intuitionistic Logic Explorer

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

Theorem notnotnot 660

Description: Triple negation. (Contributed by Jim Kingdon, 28-Jul-2018.)

**Assertion**
Ref	Expression
notnotnot

**Proof of Theorem notnotnot**
Step	Hyp	Ref	Expression
1		notnot 591	. . 3
2	1	con3i 594	. 2
3		notnot 591	. 2
4	2, 3	impbii 124	1

Colors of variables: wff set class

Syntax hints:

wn 3

wb 103

This theorem was proved from axioms: ax-1 5 ax-2 6 ax-mp 7 ax-ia2 105 ax-ia3 106 ax-in1 576 ax-in2 577

This theorem depends on definitions: df-bi 115

This theorem is referenced by: stabnot 774 testbitestn 856