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Metamath Proof Explorer

Theorem in2

Description: The virtual deduction introduction rule of converting the end virtual hypothesis of 2 virtual hypotheses into an antecedent. (Contributed by Alan Sare, 21-Apr-2011) (Proof modification is discouraged.) (New usage is discouraged.)

		Ref	Expression
	Hypothesis	in2.1	$⊢ (φ, ψ \to χ)$
	Assertion	in2	$⊢ (φ \to (ψ \to χ))$

Proof

Step	Hyp	Ref	Expression
1		in2.1	$⊢ (φ, ψ \to χ)$
2	1	dfvd2i	$⊢ φ \to (ψ \to χ)$
3	2	dfvd1ir	$⊢ (φ \to (ψ \to χ))$