Metamath Proof Explorer

Theorem dfvd1ir

Description: Inference form of df-vd1 with the virtual deduction as the assertion. (Contributed by Alan Sare, 14-Nov-2011) (Proof modification is discouraged.) (New usage is discouraged.)

Ref Expression
Hypothesis dfvd1ir.1 φ ψ
Assertion dfvd1ir φ ψ


Step Hyp Ref Expression
1 dfvd1ir.1 φ ψ
2 df-vd1 φ ψ φ ψ
3 1 2 mpbir φ ψ