PreprintCC BY-NC-SA 4.0arXiv
The e-positivity of rowDivk(eμ)
Abstract
We prove that the partition division operator rowDivk preserves e-positivity, resolving a conjecture of Alexandersson and Dai. For μ⊢ kn and ν⊢ n, we express the coefficient of eν in rowDivk(eμ) as a normalized sum of positive rational weights over closed walks on a finite directed graph of k-restricted partitions. The proof combines the Pieri rule and a root of unity factorization for Macdonald polynomials. As a corollary, we recover the h-positivity of the symmetric functions An,k of Amdeberhan, Shareshian, and Stanley.
Related
BibTeX
@misc{alexandersson2026epositivity,
title = {{The e-positivity of $\mathrmrowDiv_k(e_μ)$}},
author = {Per Alexandersson and Lilan Dai},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.26303},
eprint = {2610.26303},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.26303},
note = {CC BY-NC-SA 4.0},
}
RIS
TY - UNPB
TI - The e-positivity of rowDiv_k(e_μ)
AU - Per Alexandersson
AU - Lilan Dai
PY - 2026
DA - 2026/10/20
PB - arXiv
DO - 10.48550/arxiv.2610.26303
UR - https://arxiv.org/abs/2610.26303
AB - We prove that the partition division operator rowDiv_k preserves e-positivity, resolving a conjecture of Alexandersson and Dai. For μ⊢ kn and ν⊢ n, we express the coefficient of e_ν in rowDiv_k(e_μ) as a normalized sum of positive rational weights over closed walks on a finite directed graph of k-restricted partitions. The proof combines the Pieri rule and a root of unity factorization for Macdonald polynomials. As a corollary, we recover the h-positivity of the symmetric functions A_n,k of Amdeberhan, Shareshian, and Stanley.
ER -