Event Detail Information
Danny Calegari (University of Chicago) will present "Most groups contain surface subgroups." Abstract: We show that "most" (finitely presented) groups (in a precise sense) contain subgroups which are isomorphic to the fundamental group of a closed oriented surface of genus at least 2. The subgroups can be constructed by a (reasonably) explicit and efficient procedure. The method of construction is interesting in its own right, and involves a mixture of combinatorics and probability theory.