Speaker: Michael Anshelevich
Affiliation: Texas A&M University
Title: Inversion of non-commutative power series and Hopf algebras
Time and Place: Friday, 09/30, 12:35-1:30pm, Milner 317
Abstract: Non-commutative power series appear, for example, as joint moment series of non-commuting variables. Unlike in the commutative case, the left and the right inverses of such series are generally distinct. An effective way to describe coefficients of these inverses is as sums over certain collections of trees. These sums, in turn, can be organized by using Hopf algebras. The talk will contain a fair amount of combinatorics, but all the background will be provided.