Theorem exp42

Description: An exportation inference. (Contributed by NM, 26-Apr-1994)

	Ref	Expression
Hypothesis	exp42.1	$$⊢\left(\left(\phi \wedge \left(\psi \wedge \chi \right)\right)\wedge \theta \right)\to \tau$$
Assertion	exp42	$$⊢\phi \to \left(\psi \to \left(\chi \to \left(\theta \to \tau \right)\right)\right)$$

Proof

Step	Hyp	Ref	Expression
1		exp42.1	$$⊢\left(\left(\phi \wedge \left(\psi \wedge \chi \right)\right)\wedge \theta \right)\to \tau$$
2	1	exp31	$$⊢\phi \to \left(\left(\psi \wedge \chi \right)\to \left(\theta \to \tau \right)\right)$$
3	2	expd	$$⊢\phi \to \left(\psi \to \left(\chi \to \left(\theta \to \tau \right)\right)\right)$$