Theorem idn1

Description: Virtual deduction identity rule which is id with virtual deduction symbols. (Contributed by Alan Sare, 24-Jun-2011) (Proof modification is discouraged.) (New usage is discouraged.)

	Ref	Expression
Assertion	idn1	$$⊢\left(\phi \to \phi \right)$$

Proof

Step	Hyp	Ref	Expression
1		id	$$⊢\phi \to \phi$$
2	1	dfvd1ir	$$⊢\left(\phi \to \phi \right)$$