Theorem 3mix2i

Description: Introduction in triple disjunction. (Contributed by Mario Carneiro, 6-Oct-2014)

	Ref	Expression
Hypothesis	3mixi.1	⊢ 𝜑
Assertion	3mix2i	⊢ ( 𝜓 ∨ 𝜑 ∨ 𝜒 )

Proof

Step	Hyp	Ref	Expression
1		3mixi.1	⊢ 𝜑
2		3mix2	⊢ ( 𝜑 → ( 𝜓 ∨ 𝜑 ∨ 𝜒 ) )
3	1 2	ax-mp	⊢ ( 𝜓 ∨ 𝜑 ∨ 𝜒 )