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