Board Thread:General Discussion/@comment-34260455-20180121021230/@comment-34260455-20180129201748

Ben 10 seems to treat several alternate dimensions as alternate timelines that closely mirror our own (such as in the case of Dimension 23), so it wouldn't be a stretch to assume that alternate "dimensions" are simply alternate timelines.

Then again, interference between Prime Ben and Ben 23 don't seem to create any further alternate dimensions, so I'm at a bit of a loss as to why Dimension 23 is listed in the wiki's Alternate Timelines page. We have confirmation from The Forge of Creation that parallel universes do in fact exist, so it's unclear which direction the series takes with this concept.

If dimensions work as they should, it should be possible for a similar dimension to exist in more than 1 timeline (multiple Dimension 12's, for example). However, if "dimensions" are just how Omniverse treats alternate timelines, then Dimension 12, Dimension 23, etc. would only exist as their own respective dimensions.