Theorem ori

Description: Infer implication from disjunction. (Contributed by NM, 11-Jun-1994)

	Ref	Expression
Hypothesis	ori.1	⊢ ( 𝜑 ∨ 𝜓 )
Assertion	ori	⊢ ( ¬ 𝜑 → 𝜓 )

Proof

Step	Hyp	Ref	Expression
1		ori.1	⊢ ( 𝜑 ∨ 𝜓 )
2		df-or	⊢ ( ( 𝜑 ∨ 𝜓 ) ↔ ( ¬ 𝜑 → 𝜓 ) )
3	1 2	mpbi	⊢ ( ¬ 𝜑 → 𝜓 )