How Do You Define a Black Hole in Strength Theory?

How do you define a black hole in strength theory? Ok, so one of the really import things here is this idea that we had been starting to understand witn a lot of analytic detail. Different functions can have different in mt matics. They can have different expansions, different radii of convergences. And as you dial some parimeter like x, depending on where you are, one expansion might be better than the other. That's back by therung theory thing.