Metamath Proof Explorer


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,χφ

Proof

Step Hyp Ref Expression
1 vd02.1 φ
2 1 a1i χφ
3 2 a1i ψχφ
4 3 dfvd2ir ψ,χφ