Theorem vd02

Description: Two virtual hypotheses virtually infer a theorem. (Contributed by Alan Sare, 14-Jun-2011) (Proof modification is discouraged.) (New usage is discouraged.)

	Ref	Expression
Hypothesis	vd02.1	⊢ 𝜑
Assertion	vd02	⊢ (    𝜓    ,    𝜒    ▶    𝜑    )

Proof

Step	Hyp	Ref	Expression
1		vd02.1	⊢ 𝜑
2	1	a1i	⊢ ( 𝜒 → 𝜑 )
3	2	a1i	⊢ ( 𝜓 → ( 𝜒 → 𝜑 ) )
4	3	dfvd2ir	⊢ (    𝜓    ,    𝜒    ▶    𝜑    )