Theorem necom

Description: Commutation of inequality. (Contributed by NM, 14-May-1999)

	Ref	Expression
Assertion	necom	⊢ ( 𝐴 ≠ 𝐵 ↔ 𝐵 ≠ 𝐴 )

Proof

Step	Hyp	Ref	Expression
1		eqcom	⊢ ( 𝐴 = 𝐵 ↔ 𝐵 = 𝐴 )
2	1	necon3bii	⊢ ( 𝐴 ≠ 𝐵 ↔ 𝐵 ≠ 𝐴 )