Abstract

We give explicit combinatorial product formulas for the maximal parabolic Kazhdan-Lusztig and R-polynomials of the symmetric group. These formulas imply that these polynomials are combinatorial invariants, and that the Kazhdan-Lusztig ones are nonnegative. The combinatorial formulas are most naturally stated in terms of Young’s lattice, and the one for the Kazhdan-Lusztig polynomials depends on a new class of skew partitions which are closely related to Dyck paths.

Authors