|Date: Friday, October 27, 2017
Location: 4088 East Hall (4:10 PM to 5:00 PM)
Title: Topology of totally positive spaces
Abstract: Total positivity is the study of spaces and their positive parts. For example, the positive part of the space of n x n real matrices is formed by those matrices whose every submatrix has positive determinant. Such spaces often have interesting combinatorial properties as well as diverse applications. In this talk, I will discuss two motivations for studying the topology of positive spaces: one comes from poset combinatorics, the other from new developments in high-energy physics. I will then present joint work with Pavel Galashin and Thomas Lam, which shows that the closure of the positive part of a Grassmannian is homeomorphic to a closed ball. The proof exploits the cyclic symmetry of the positive Grassmannian.
Speaker: Steven Karp
Institution: U. Michigan