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Metamath Proof Explorer

Theorem jarl

Description: Elimination of a nested antecedent. (Contributed by Wolf Lammen, 10-May-2013)

		Ref	Expression
	Assertion	jarl	$⊢ ((φ \to ψ) \to χ) \to (\neg φ \to χ)$

Step	Hyp	Ref	Expression
1		pm2.21	$⊢ \neg φ \to (φ \to ψ)$
2	1	imim1i	$⊢ ((φ \to ψ) \to χ) \to (\neg φ \to χ)$