Theorem exa1

Description: Add an antecedent in an existentially quantified formula. (Contributed by BJ, 6-Oct-2018)

	Ref	Expression
Assertion	exa1	$$⊢\exists x\phi \to \exists x\left(\psi \to \phi \right)$$

Proof

Step	Hyp	Ref	Expression
1		ax-1	$$⊢\phi \to \left(\psi \to \phi \right)$$
2	1	eximi	$$⊢\exists x\phi \to \exists x\left(\psi \to \phi \right)$$