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Metamath Proof Explorer

Theorem dfvd2impr

Description: A 2-antecedent nested implication implies its virtual deduction form. (Contributed by Alan Sare, 21-Apr-2011) (Proof modification is discouraged.) (New usage is discouraged.)

		Ref	Expression
	Assertion	dfvd2impr	$⊢ (φ \to (ψ \to χ)) \to (φ, ψ \to χ)$

Proof

Step	Hyp	Ref	Expression
1		dfvd2	$⊢ (φ, ψ \to χ) \leftrightarrow (φ \to (ψ \to χ))$
2	1	biimpri	$⊢ (φ \to (ψ \to χ)) \to (φ, ψ \to χ)$