Solving Problems with Total Nonnegativity

04/04/2017 - 12:15pm
04/04/2017 - 1:10pm
Sian Fryer (University of California Santa Barbara)

A totally nonnegative matrix is a matrix with the property that all of its minors are positive or zero. It's a simple definition, but it leads to a wide range of interesting combinatorics and produces tools which can be used to study everything from noncommutative rings to quantum field theory. The talk will start with some background on total nonnegativity, followed by an introduction to Grassmann necklaces (currently my favourite parametrization of the totally nonnegative cells), and finally several examples of problems for which Grassmann necklaces turned out to be a very natural answer.

ML 2099