Grothendieck-to-Lascoux expansions

We establish the conjecture of Reiner and Yong for an explicit combinatorial formula expansion a Grothendieck polynomial into basis Lascoux polynomials. This is subtle refinement its symmetric function version due to Buch, Kresch, Shimozono, Tamvakis, Yong, which gives stable polynomials indexed by permutations Grassmannian Our K K -theoretic analogue that Schubert Demazure characters, whose Stanley Schur functions. expansions extend flagged