Metamath Proof Explorer


Theorem neii

Description: Inference associated with df-ne . (Contributed by BJ, 7-Jul-2018)

Ref Expression
Hypothesis neii.1 A B
Assertion neii ¬ A = B

Proof

Step Hyp Ref Expression
1 neii.1 A B
2 df-ne A B ¬ A = B
3 1 2 mpbi ¬ A = B