Here is a start at a glossary: UD - The Universal Dovetailer, a hypothetical system for running all possible computer programs. See UDA.

UDA - The Universal Dovetailer Argument of Bruno Marchal, which concludes that we must derive the laws of physics from computer science. See http://www.escribe.com/science/theory/m3044.html. Level 1, 2, 3, 4 multiverses - These are based on Max Tegmark's hierarchy, described at http://www.hep.upenn.edu/~max/multiverse1.html. Briefly, the level 1 multiverse consists of regions of space within our universe that are beyond our observation horizon. Level 2 is the multiple bubbles of space predicted by inflation theory. Level 3 is the Many-Worlds Interpretation of Quantum Mechanics (MWI). Level 4 is the hypothesis that all mathematical structures exist and that some of them can be though of as universes. MWI - The Many-Worlds Interpretation of Quantum Mechanics, which holds that at every quantum event the universe splits into parallel worlds. See http://www.hep.upenn.edu/~max/everett.html for Tegmark's version. Also see the level 3 multiverse reference for more links. For the following, I don't have links, and my definitions may not be quite right, so I invite corrections and links to definitions. SSA - The Self-Sampling Assumption, which says that you should consider yourself as a randomly sampled observer from among all observers in the multiverse. SSSA - The Strong Self-Sampling Assumption, which says that you should consider this particular observer-moment you are experiencing as being randomly sampled from among all observer-moments in the universe. ASSA - The Absolute Self-Sampling Assumption, which says that you should consider your next observer-moment to be randomly sampled from among all observer-moments in the universe. RSSA - The Relative Self-Sampling Assumption, which says that you should consider your next observer-moment to be randomly sampled from among all observer-moments which come immediately after your current observer-moment and belong to the same observer. Hal