Theorem necomd

Description: Deduction from commutative law for inequality. (Contributed by NM, 12-Feb-2008)

	Ref	Expression
Hypothesis	necomd.1	$$⊢\phi \to A\ne B$$
Assertion	necomd	$$⊢\phi \to B\ne A$$

Proof

Step	Hyp	Ref	Expression
1		necomd.1	$$⊢\phi \to A\ne B$$
2		necom	$$⊢A\ne B\leftrightarrow B\ne A$$
3	1 2	sylib	$$⊢\phi \to B\ne A$$