Saturation for Non-Symmetric Macdonald Polynomials

Abstract: We prove that supports of non-symmetric Macdonald polynomials are $M$-convex. As a consequence, we resolve a 2019 conjecture of Monical, Tokcan, and Yong that they have the saturated Newton polytope property. As a further consequence, we prove that the moment polytopes of affine Schubert varieties in the affine Grassmannian of type $\mathrm{GL}$ are generalized permutahedra.