Theorem exbiii

Description: Inference associated with exbii . Weaker version of eximii . (Contributed by SN, 14-Oct-2025)

	Ref	Expression
Hypotheses	exbiii.1	$$⊢\exists x\phi$$
	exbiii.2	$$⊢\phi \leftrightarrow \psi$$
Assertion	exbiii	$$⊢\exists x\psi$$

Proof

Step	Hyp	Ref	Expression
1		exbiii.1	$$⊢\exists x\phi$$
2		exbiii.2	$$⊢\phi \leftrightarrow \psi$$
3	2	biimpi	$$⊢\phi \to \psi$$
4	1 3	eximii	$$⊢\exists x\psi$$