I read the same article, and was able to follow some of it. First off, I should mention that this is just one approach to understanding the nature of space-time. String theory and loop quantum gravity are competitors. All of these are by definition attempts to find a mathematical framework 'joining these two pillars of physics'.
Certainly ordinary General Relativity, a 4-D theory, only emerges at some spatial scale, with a different description applying on smaller scales. That's a pretty general feature of all attempts to integrate relativity and quantum mechanics.
As I understand the article (we'll update if better information comes in from colleagues) the assumption is that quantum rules apply all the way down, in all dimensions. It looks like the choice of 4-simplices as the basic ingredients may put in the large-scale 4-D behavior by hand, although I'm not sure. It also looks like this theory, unlike some hoped-for string results, does not integrate gravity with the other (nuclear and electrical) forces.
Mike W.
(published on 07/13/2008)