How are you defining the word “universe”? Is it in a hypothetical imagined virtual universe? If so then yes, that happens regularly in mathematics (eg Carl Sagan’s flatworld). If you’re asking “are there multiple real universes in reality with some kind of relationship between them” we don’t know yet and until we have a falsifiable theory that withstands experiments we won’t know. Mathematics can be used to prove certain properties in the absence of those experiments and to explain how a theory might be falsifiable. An example of this would be string theory. Mathematically self-consistent, all available evidence seems to be against it (can’t recall if it was finally disproven or still just highly unlikely to be true)
