Theorem idn2

Description: Virtual deduction identity rule which is idd with virtual deduction symbols. (Contributed by Alan Sare, 21-Apr-2011) (Proof modification is discouraged.) (New usage is discouraged.)

	Ref	Expression
Assertion	idn2	⊢ (    𝜑    ,    𝜓    ▶    𝜓    )

Proof

Step	Hyp	Ref	Expression
1		idd	⊢ ( 𝜑 → ( 𝜓 → 𝜓 ) )
2	1	dfvd2ir	⊢ (    𝜑    ,    𝜓    ▶    𝜓    )