Theorem a1i13

Description: Add two antecedents to a wff. (Contributed by Jeff Hankins, 4-Aug-2009)

	Ref	Expression
Hypothesis	a1i13.1	$$⊢\psi \to \theta$$
Assertion	a1i13	$$⊢\phi \to \left(\psi \to \left(\chi \to \theta \right)\right)$$

Proof

Step	Hyp	Ref	Expression
1		a1i13.1	$$⊢\psi \to \theta$$
2	1	a1d	$$⊢\psi \to \left(\chi \to \theta \right)$$
3	2	a1i	$$⊢\phi \to \left(\psi \to \left(\chi \to \theta \right)\right)$$