Theorem vd03

Description: A theorem is virtually inferred by the 3 virtual hypotheses. (Contributed by Alan Sare, 12-Jun-2011) (Proof modification is discouraged.) (New usage is discouraged.)

	Ref	Expression
Hypothesis	vd03.1	$$⊢\phi$$
Assertion	vd03	$$⊢\left(\psi ,\chi ,\theta \to \phi \right)$$

Proof

Step	Hyp	Ref	Expression
1		vd03.1	$$⊢\phi$$
2	1	a1i	$$⊢\theta \to \phi$$
3	2	a1i	$$⊢\chi \to \left(\theta \to \phi \right)$$
4	3	a1i	$$⊢\psi \to \left(\chi \to \left(\theta \to \phi \right)\right)$$
5	4	dfvd3ir	$$⊢\left(\psi ,\chi ,\theta \to \phi \right)$$