Metamath Proof Explorer


Theorem pm2.18i

Description: Inference associated with the Clavius law pm2.18 . (Contributed by BJ, 30-Mar-2020)

Ref Expression
Hypothesis pm2.18i.1 ⊢ ¬ φ → φ
Assertion pm2.18i ⊢ φ

Proof

Step Hyp Ref Expression
1 pm2.18i.1 ⊢ ¬ φ → φ
2 pm2.18 ⊢ ¬ φ → φ → φ
3 1 2 ax-mp ⊢ φ