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Theorem stabnot 741

Description: Every formula of the form

is stable. Uses notnotnot 628. (Contributed by David A. Wheeler, 13-Aug-2018.)

**Assertion**
Ref	Expression
stabnot	STAB

**Proof of Theorem stabnot**
Step	Hyp	Ref	Expression
1		notnotnot 628	. . 3
2	1	biimpi 113	. 2
3		df-stab 740	. 2 STAB
4	2, 3	mpbir 134	1 STAB

Colors of variables: wff set class

Syntax hints:

wn 3

wi 4 STAB wstab 739

This theorem was proved from axioms: ax-1 5 ax-2 6 ax-mp 7 ax-ia1 99 ax-ia2 100 ax-ia3 101 ax-in1 544 ax-in2 545

This theorem depends on definitions: df-bi 110 df-stab 740

This theorem is referenced by: (None)