Theorem vd01

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

	Ref	Expression
Hypothesis	vd01.1	⊢ 𝜑
Assertion	vd01	⊢ (    𝜓    ▶    𝜑    )

Proof

Step	Hyp	Ref	Expression
1		vd01.1	⊢ 𝜑
2	1	a1i	⊢ ( 𝜓 → 𝜑 )
3	2	dfvd1ir	⊢ (    𝜓    ▶    𝜑    )