Avery St. Dizier

Double orthodontia formulas and Lascoux positivity

We give a new formula for double Grothendieck polynomials based on Magyar’s orthodontia algorithm for diagrams. Our formula implies a similar formula for double Schubert polynomials 𝔖 w ( x ; y ) . We also prove a curious positivity result: for vexillary permutations w ∈ S n , th...