Theorem nanor

Description: Alternative denial in terms of disjunction and negation. This explains the name "alternative denial". (Contributed by BJ, 19-Oct-2022)

	Ref	Expression
Assertion	nanor	|- ( ( ph -/\ ps ) <-> ( -. ph \/ -. ps ) )

Proof

Step	Hyp	Ref	Expression
1		df-nan	|- ( ( ph -/\ ps ) <-> -. ( ph /\ ps ) )
2		ianor	|- ( -. ( ph /\ ps ) <-> ( -. ph \/ -. ps ) )
3	1 2	bitri	|- ( ( ph -/\ ps ) <-> ( -. ph \/ -. ps ) )