The MathNet Korea
Information Center for Mathematical Science

세미나

Information Center for Mathematical Science

세미나

한국고등과학원 세미나
Title Top heaviness and hard Lefschetz
Date 2018-10-26
Speaker Geordie Williamson(University of Sydney)
Sponsors 2018-10-26
Host KIAS
Place 1503
Abstract Consider an object of “dimension n” and the set of its subobjects of “dimension i”. For example, we might consider a polytope and its faces, or a partition and its subpartitions. Often the number of subobjects of “dimension i” is less than or equal to the number of objects of “dimension n-i”, for i between 0 and n/2. I will explain why this phenomenon is a shadow of the hard Lefschezt theorem. I will then explain the very interesting case of Coxeter group elements and Bruhat order, and try to describe what we do and don’t know.