Welcome KSE Mathematics Seminar on Wednesday:
 
“Connecting matrices and plabic graphs”
 
Speaker: Olha Shevchenko (PhD student, University of California, Los Angeles)
 
🗓When: December 17, 16:30-17:30
📍Where: KSE Dragon Capital Building, 3 Mykoly Shpaka St., Room 4.05

Abstract:
In this talk, will introduce background on the totally nonnegative Grassmannian $Gr_{\geq 0}(k,n)$, a space corresponding to matrices whose maximal minors are all nonnegative. It was shown by Postnikov that points of $Gr_{\geq 0}(k,n)$ can be represented using so-called plabic graphs, allowing for the study of the totally nonnegative Grassmannian and its subspaces combinatorially.

We will also address the following question: Which points of $Gr_{\geq 0}(k,n)$ can be represented by centrally symmetric plabic graphs? I will describe this new space (called totally nonnegative Lagrangian Grassmannian), and outline its algebraic, geometric and combinatorial structure.