Authors: Edward Richmond ¹; Vasu Tewari ²; Stephanie Van Willigenburg

• 1 Oklahoma State University [Stillwater]
• 2 University of Washington [Seattle]

The geometric Littlewood-Richardson (LR) rule is a combinatorial algorithm for computing LR coefficients derived from degenerating the Richardson variety into a union of Schubert varieties in the Grassmannian. Such rules were first given by Vakil and later generalized by Coskun. In this paper we give a noncommutative version of the geometric LR rule. As a consequence, we establish a geometric explanation for the positivity of noncommutative LR coefficients in certain cases.