this thread focuses on the May 2001 paper of Ambjorn Jurkiewicz Loll called Dynamically Triangulating Lorentzian Quantum Gravity http://arxiv.org/hep-th/0105267 [Broken] It may be that this will turn out to have been the historical landmark paper because this year we have had two confirming followup papers from AJL showing that they got their approach (mapped out in 2001) to work in 4D. It starts with no space and time, but with hundreds of thousands of things like (4D) tetrahedrons. And a combinatorial spacetime grows from them. according to a propagator. and more conventional macroscopic space and time features emerge at large scale from this more fundamental microscopic picture. so it has the kind of features you'd like to see in a theory of Quantum Gravity----a general relativistic quantum theory of space and time---and it provides an interesting venue where matter could be added to the picture and studied in this new quantum spacetime context. In this 2001 paper, AJL are laying out their program. they give a lot more detail here than they do later in the papers where they report that the program is working. what they are proposing in this (I think landmark) early paper is the Monte Carlo computer runs of emerging 4D spacetime that they then went and did and reported later. Because its more detailed and nittygritty, it seems more accessible. this is the paper that the ones this year refer back to. So I guess it is basic. Let's see if we can get somewhere with it. Remember that when this paper appeared, String approaches had been attempted for over 20 years, and Loop approaches for over 10 years.