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Metamath Proof Explorer

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