Theorem olci

Description: Deduction introducing a disjunct. (Contributed by NM, 19-Jan-2008) (Proof shortened by Wolf Lammen, 14-Nov-2012)

	Ref	Expression
Hypothesis	orci.1	⊢ 𝜑
Assertion	olci	⊢ ( 𝜓 ∨ 𝜑 )

Proof

Step	Hyp	Ref	Expression
1		orci.1	⊢ 𝜑
2	1	a1i	⊢ ( ¬ 𝜓 → 𝜑 )
3	2	orri	⊢ ( 𝜓 ∨ 𝜑 )