Equivariant Schubert calculus and jeu de taquin

Abstract

We introduce edge labeled Young tableaux. Our main results provide a corresponding analogue of [Sch\"{u}tzenberger '77]'s theory of jeu de taquin. These are applied to the equivariant Schubert calculus of Grassmannians. Reinterpreting, we present new (semi)standard tableaux to study factorial Schur polynomials, after [Biedenharn-Louck '89], [Macdonald '92] and [Goulden-Greene '94] and others. Consequently, we obtain new combinatorial rules for the Schubert structure coefficients, complementing work of [Molev-Sagan '99], [Knutson-Tao '03], [Molev '08] and [Kreiman '09]. We also describe a conjectural generalization of one of our rules to the equivariant K-theory of Grassmannians, extending work of [Thomas-Yong '07]. This conjecture concretely realizes the "positivity" known to exist by [Anderson-Griffeth-Miller '08]. It provides an alternative to the conjectural rule of Knutson-Vakil reported in [Coskun-Vakil '06].