Theorem pm2.83 84

Description: Theorem *2.83 of [WhiteheadRussell] p. 108. Closed form of syld 47. (Contributed by NM, 3-Jan-2005.)

Assertion

Ref	Expression
pm2.83	⊢ ((𝜑 → (𝜓 → 𝜒)) → ((𝜑 → (𝜒 → 𝜃)) → (𝜑 → (𝜓 → 𝜃))))

Proof of Theorem pm2.83

Step	Hyp	Ref	Expression
1		imim1 83	. 2 ⊢ ((𝜓 → 𝜒) → ((𝜒 → 𝜃) → (𝜓 → 𝜃)))
2	1	imim3i 64	1 ⊢ ((𝜑 → (𝜓 → 𝜒)) → ((𝜑 → (𝜒 → 𝜃)) → (𝜑 → (𝜓 → 𝜃))))

Syntax hints:   → wi 4

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

This theorem is referenced by:  rexrsb  43289