Getting unstable neurons with alpha-beta crown

[Dalnaracrater]

Hello,
Thank you for your dedication to the research community.

I have a question about obtaining unstable neurons in the context of verification research. Specifically, I noticed that some works mention authors identify unstable neurons using $\alpha\beta$ CROWN. However, I am unsure at which step these neurons are typically obtained.

Please correct me if I am wrong: For instance, is it during incomplete verification using $\alpha$ CROWN through LiRPA? Or during complete verification with $\alpha\beta$ CROWN (and if so, is it before or after the bound optimization process)?

Is there a commonly accepted context or step in the research field where unstable neurons are identified?

Thank you again for your insights