The Quasisymmetric Flag Variety

Attend a 2-hour lecture titled "The Quasisymmetric Flag Variety" delivered by Hunter Spink from the University of Toronto as part of the Special Year Seminar II at the Institute for Advanced Study. Scheduled for March 20, 2025, this mathematical talk explores the construction of a "quasisymmetric flag variety," a subvariety of the complete type A flag variety that adapts the BGG geometric construction of divided differences to "quasisymmetric divided differences." Learn how its cohomology ring relates to quasisymmetric coinvariants and how it's paved by Weyl group translates of "Coxeter Richardson varieties." Discover the new concept of "equivariant quasisymmetry" emerging from the torus-equivariant geometry study, leading to "double fundamental quasisymmetric polynomials" and "double forest polynomials" with Graham-positive multiplication structure constants. This research represents joint work with Nantel Bergeron, Lucas Gagnon, Philippe Nadeau, and Vasu Tewari.