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Metamath Proof Explorer

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	$⊢ (ψ \to φ)$

Proof

Step	Hyp	Ref	Expression
1		vd01.1	$⊢ φ$
2	1	a1i	$⊢ ψ \to φ$
3	2	dfvd1ir	$⊢ (ψ \to φ)$