Theorem bj-19.23bit

Description: Closed form of 19.23bi . (Contributed by BJ, 20-Oct-2019)

	Ref	Expression
Assertion	bj-19.23bit	$$⊢\left(\exists x\phi \to \psi \right)\to \left(\phi \to \psi \right)$$

Proof

Step	Hyp	Ref	Expression
1		19.8a	$$⊢\phi \to \exists x\phi$$
2	1	imim1i	$$⊢\left(\exists x\phi \to \psi \right)\to \left(\phi \to \psi \right)$$