Colloquium: Khrystyna Serhiyenko (UC Berkeley)

February 26, 2018 @ 3:30 pm – 4:30 pm

Speaker: Khrystyna Serhiyenko  (UC Berkeley)

Title: Frieze patterns 

Abstract: Frieze is a lattice of positive integers satisfying certain rules.  Friezes were first studied by Conway and Coxeter in 1970′s, but they gained fresh interest in the last decade in relation to cluster algebras.  In particular, there exists a bijection between friezes and cluster algebras of type A.  Moreover, the categorification of cluster algebras developed in 2006 yields a new realization of friezes in terms of representation theory of Jacobian algebras.  In this talk, we will discuss the beautiful connections between all these objects.  

An operation called mutation is the key notion in cluster algebras.  We will introduce a compatible notion of mutation for friezes and describe the resulting entries using combinatorics of quiver representations.  We will also mention an important generalization of the classical friezes, called sl_k friezes and their connections to Grassmannians Gr(k,n).