Theorem jarl 648

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

Assertion

Ref	Expression
jarl	⊢ (((𝜑 → 𝜓) → 𝜒) → (¬ 𝜑 → 𝜒))

Proof of Theorem jarl

Step	Hyp	Ref	Expression
1		pm2.21 607	. 2 ⊢ (¬ 𝜑 → (𝜑 → 𝜓))
2	1	imim1i 60	1 ⊢ (((𝜑 → 𝜓) → 𝜒) → (¬ 𝜑 → 𝜒))

Syntax hints:  ¬ wn 3   → wi 4

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-in2 605

This theorem is referenced by:  pm2.68dc  884