Partition division maps, symmetric functions and positivity

Fuente: arXiv
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Main Authors: Alexandersson, Per, Dai, Lilan
Format: Preprint
Published: 2026
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author Alexandersson, Per
Dai, Lilan
author_facet Alexandersson, Per
Dai, Lilan
contents We study a linear map on symmetric functions that ``divides'' a partition by a positive integer $k$, sending a Schur function indexed by a partition of $kn$ to a symmetric function indexed by partitions of $n$. We determine its Schur expansion explicitly for Schur and skew Schur functions, showing that the coefficients are enumerated by a new family of combinatorial objects, called $k$-Yamanouchi tableaux, which generalize the classical ballot (Yamanouchi) tableaux appearing in the Littlewood--Richardson rule. We also study the images of elementary symmetric functions under this map, derive the power-sum expansion of their $ω$-images, and establish power-sum positivity. A further application establishes a connection to work of Tewodros Amdeberhan, John Shareshian, and Richard Stanley on alternating permutations and Euler numbers.
format Preprint
id arxiv_https___arxiv_org_abs_2604_25440
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Partition division maps, symmetric functions and positivity
Alexandersson, Per
Dai, Lilan
Combinatorics
Representation Theory
05E05, 05A17, 05A19
We study a linear map on symmetric functions that ``divides'' a partition by a positive integer $k$, sending a Schur function indexed by a partition of $kn$ to a symmetric function indexed by partitions of $n$. We determine its Schur expansion explicitly for Schur and skew Schur functions, showing that the coefficients are enumerated by a new family of combinatorial objects, called $k$-Yamanouchi tableaux, which generalize the classical ballot (Yamanouchi) tableaux appearing in the Littlewood--Richardson rule. We also study the images of elementary symmetric functions under this map, derive the power-sum expansion of their $ω$-images, and establish power-sum positivity. A further application establishes a connection to work of Tewodros Amdeberhan, John Shareshian, and Richard Stanley on alternating permutations and Euler numbers.
title Partition division maps, symmetric functions and positivity
topic Combinatorics
Representation Theory
05E05, 05A17, 05A19
url https://arxiv.org/abs/2604.25440