Theorem vd12 44620

Description: A virtual deduction with 1 virtual hypothesis virtually inferring a virtual conclusion infers that the same conclusion is virtually inferred by the same virtual hypothesis and an additional hypothesis. (Contributed by Alan Sare, 12-Jun-2011.) (Proof modification is discouraged.) (New usage is discouraged.)

Hypothesis

Ref	Expression
vd12.1	⊢ (   𝜑   ▶   𝜓   )

Assertion

Ref	Expression
vd12	⊢ (   𝜑   ,   𝜒   ▶   𝜓   )

Proof of Theorem vd12

Step	Hyp	Ref	Expression
1		vd12.1	. . . 4 ⊢ (   𝜑   ▶   𝜓   )
2	1	in1 44591	. . 3 ⊢ (𝜑 → 𝜓)
3	2	a1d 25	. 2 ⊢ (𝜑 → (𝜒 → 𝜓))
4	3	dfvd2ir 44606	1 ⊢ (   𝜑   ,   𝜒   ▶   𝜓   )

Syntax hints:  (   wvd1 44589  (   wvd2 44597

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8

This theorem depends on definitions:  df-bi 207  df-an 396  df-vd1 44590  df-vd2 44598

This theorem is referenced by:  e221  44669  e212  44671  e122  44673  e112  44674  e121  44676  e211  44677  e120  44683  e12  44744  e21  44750