Theorem nabi2i

Description: Constructor rule for -/\ . (Contributed by Anthony Hart, 2-Sep-2011)

	Ref	Expression
Hypotheses	nabi2i.1	|- ( ph <-> ps )
	nabi2i.2	|- ( ch -/\ ps )
Assertion	nabi2i	|- ( ch -/\ ph )

Proof

Step	Hyp	Ref	Expression
1		nabi2i.1	|- ( ph <-> ps )
2		nabi2i.2	|- ( ch -/\ ps )
3	1	bicomi	|- ( ps <-> ph )
4	3	nanbi2i	|- ( ( ch -/\ ps ) <-> ( ch -/\ ph ) )
5	2 4	mpbi	|- ( ch -/\ ph )