My long answer: Complete and total lack of mathematical definition, from what little I understand of these notions. Your question goes “in between spaces”, instead of “different spaces”. My assumption is thus that you're asking about something outside of space-time models in their totality. That's where the problem would start, because the usual universal model is mathematically consistent enough that “between spaces” or “outside all spacetime” often constitutes nonsense. But my potential future with physics pulls at my shoulder right now, saying “Don't sound smart about things you don't know either.”
My short answer: Complete and total lack of mathematical definition, I think. Keyword right there.
My even shorter answer (and the alternative I'd pick): Sometimes, we all have to say “I have no idea.”
Having stablished this and for future reference, your wording is vague for a question this complicated. People trying to answer have to assume a substantial amount of things about it, before they can even try to answer.