Theorem pm2.83 71

Description: Theorem *2.83 of [WhiteheadRussell] p. 108. (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 70	. 2 ⊢ ((ψ → χ) → ((χ → θ) → (ψ → θ)))
2	1	imim3i 55	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: (None)