Description: Nonvirtual deduction form of e33 41813. (Contributed by Alan Sare,
18Mar2012.) (Proof modification is discouraged.)
(New usage is discouraged.)
The following User's Proof is a Virtual Deduction proof
completed automatically by the tools program completeusersproof.cmd,
which invokes Mel L. O'Cat's mmj2 and Norm Megill's Metamath Proof
Assistant. The completed Virtual Deduction Proof (not shown) was
minimized. The minimized proof is shown.
h1::  ⊢ (𝜑 → (𝜓 → (𝜒 → 𝜃)))
 h2::  ⊢ (𝜑 → (𝜓 → (𝜒 → 𝜏)))
 h3::  ⊢ (𝜃 → (𝜏 → 𝜂))
 4:1,3:  ⊢ (𝜑 → (𝜓 → (𝜒 → (𝜏 → 𝜂))))
 5:4:  ⊢ (𝜏 → (𝜑 → (𝜓 → (𝜒 → 𝜂))))
 6:2,5:  ⊢ (𝜑 → (𝜓 → (𝜒 → (𝜑 → (𝜓 →
(𝜒 → 𝜂))))))
 7:6:  ⊢ (𝜓 → (𝜒 → (𝜑 → (𝜓 → (𝜒 →
𝜂)))))
 8:7:  ⊢ (𝜒 → (𝜑 → (𝜓 → (𝜒 → 𝜂))))
 qed:8:  ⊢ (𝜑 → (𝜓 → (𝜒 → 𝜂)))

