Theorem 2a1dd

Description: Double deduction introducing two antecedents. Two applications of 2a1dd . Deduction associated with 2a1d . Double deduction associated with 2a1 and 2a1i . (Contributed by Jeff Hankins, 5-Aug-2009)

	Ref	Expression
Hypothesis	2a1dd.1	$$⊢\phi \to \left(\psi \to \chi \right)$$
Assertion	2a1dd	$$⊢\phi \to \left(\psi \to \left(\theta \to \left(\tau \to \chi \right)\right)\right)$$

Proof

Step	Hyp	Ref	Expression
1		2a1dd.1	$$⊢\phi \to \left(\psi \to \chi \right)$$
2	1	a1dd	$$⊢\phi \to \left(\psi \to \left(\tau \to \chi \right)\right)$$
3	2	a1dd	$$⊢\phi \to \left(\psi \to \left(\theta \to \left(\tau \to \chi \right)\right)\right)$$