Theorem pm2.86i

Description: Inference associated with pm2.86 . (Contributed by NM, 5-Aug-1993) (Proof shortened by Wolf Lammen, 3-Apr-2013)

	Ref	Expression
Hypothesis	pm2.86i.1	$$⊢\left(\phi \to \psi \right)\to \left(\phi \to \chi \right)$$
Assertion	pm2.86i	$$⊢\phi \to \left(\psi \to \chi \right)$$

Proof

Step	Hyp	Ref	Expression
1		pm2.86i.1	$$⊢\left(\phi \to \psi \right)\to \left(\phi \to \chi \right)$$
2	1	jarri	$$⊢\psi \to \left(\phi \to \chi \right)$$
3	2	com12	$$⊢\phi \to \left(\psi \to \chi \right)$$