Title: Pattern avoidance and fiber bundle structures on Schubert varieties
Speaker: Edward Richmond (Oklahoma State University)
Abstract: In this talk, I will discuss joint work with Tim Alland where we give a pattern avoidance criteria for determining when the projection map from the flag variety to a Grassmannian induces a fiber bundle structure on a Schubert variety. To do this, we introduce the notion of split pattern avoidance and show that a Schubert variety has such a fiber bundle structure if and only if the corresponding permutation avoids the split patterns 3|12 and 23|1. Continuing, we also characterize when a Schubert variety is an iterated fiber bundle of Grassmannian Schubert varieties in terms of usual pattern avoidance.
Seminar URL: https://people.math.osu.edu/anderson.2804/gcis/