On the minimal power of in a Kazhdan-Lusztig polynomial
arXiv:2303.13695 · doi:10.1016/j.aim.2024.109941
Abstract
For in the symmetric group, we provide an exact formula for the smallest positive power appearing in the Kazhdan-Lusztig polynomial . We also provide a tight upper bound on in simply-laced types, resolving a conjecture of Billey-Postnikov from 2002.
24 pages. v2: minor corrections, to appear in Advances in Math