Sum over topologies---Loll Westra this thread is about these three papers http://arxiv.org/hep-th/0306183 http://arxiv.org/hep-th/0309012 http://arxiv.org/hep-th/0507012 the titles are "sum over topologies and...." "spacetime foam in 2D and the sum over topologies" "taming the cosmological constant in 2D causal quantum gravity with topology change" I want to discuss these papers, if someone wants to with me. I think they are important. what happened before with Loll was she got something (CDT) to work in 2D in 1998 (she and Ambjorn) and then gradually they cranked it up to 3D and then finally in 2004 they got it working in 4D. and the way you understand Loll work in 4D is NOT approach it directly but begin studying how it works in lower dimensions. when she finally gets this "sum over topologies" to work in 4D and the paper comes out, then if you want to understand it you will STILL have to go back to these three here! I guarantee as much as anyone can guarantee about the future. In 2006 or so you are going to wish you had read these 3 papers, or if you did read them then you will be glad.