Theorem imori

Description: Infer disjunction from implication. (Contributed by NM, 12-Mar-2012)

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

Proof

Step	Hyp	Ref	Expression
1		imori.1	⊢ ( 𝜑 → 𝜓 )
2		imor	⊢ ( ( 𝜑 → 𝜓 ) ↔ ( ¬ 𝜑 ∨ 𝜓 ) )
3	1 2	mpbi	⊢ ( ¬ 𝜑 ∨ 𝜓 )