Theorem wl-impchain-a1-3

Description: Inference rule, a copy of a1dd . A recursive proof depending on previous instances, and demonstrating the proof pattern. (Contributed by Wolf Lammen, 20-Jun-2020) (New usage is discouraged.) (Proof modification is discouraged.)

	Ref	Expression
Hypothesis	wl-impchain-a1-3.a	$$⊢\phi \to \left(\psi \to \chi \right)$$
Assertion	wl-impchain-a1-3	$$⊢\phi \to \left(\psi \to \left(\theta \to \chi \right)\right)$$

Proof

Step	Hyp	Ref	Expression
1		wl-impchain-a1-3.a	$$⊢\phi \to \left(\psi \to \chi \right)$$
2	1	wl-impchain-a1-2	$$⊢\phi \to \left(\theta \to \left(\psi \to \chi \right)\right)$$
3	2	wl-impchain-com-2.3	$$⊢\phi \to \left(\psi \to \left(\theta \to \chi \right)\right)$$