Hi Tim - TY again for a non-mathematical description of some very nice work. I understand (to a degree, of course) how a 5th dimension to Gen Relativity adds an additional curvature which we experience as a force, ie, electro-magnetism, &, as such, really wouldn't need any compactification, as the curvature we call a 'dimension' is not at all hidden.

My question is that, as the natural number of dimensions, ala M-Theory, may be 11, could one extend Gen Relativity to also pop out the Strong and Weak Forces, as well as, ... I don't know what?

Would that geometric approach yield something that's testable, as ... I don't think we'll build a particle accelerator the size of the Milky Way anytime soon.

Anyway, thanks again! It's always a pleasure reading your work.