Theorem nabi12i

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

	Ref	Expression
Hypotheses	nabi12i.1	|- ( ph <-> ps )
	nabi12i.2	|- ( ch <-> th )
	nabi12i.3	|- ( ps -/\ th )
Assertion	nabi12i	|- ( ph -/\ ch )

Proof

Step	Hyp	Ref	Expression
1		nabi12i.1	|- ( ph <-> ps )
2		nabi12i.2	|- ( ch <-> th )
3		nabi12i.3	|- ( ps -/\ th )
4	1 3	nabi1i	|- ( ph -/\ th )
5	2 4	nabi2i	|- ( ph -/\ ch )