Metamath Proof Explorer


Theorem bj-nimni

Description: Inference associated with bj-nimn . (Contributed by BJ, 19-Mar-2020)

Ref Expression
Hypothesis bj-nimni.1 ⊢ φ
Assertion bj-nimni ⊢ ¬ φ → ¬ φ

Proof

Step Hyp Ref Expression
1 bj-nimni.1 ⊢ φ
2 bj-nimn ⊢ φ → ¬ φ → ¬ φ
3 1 2 ax-mp ⊢ ¬ φ → ¬ φ