PreprintarXiv licencearXiv
Berenstein-Zelevinsky polytopes for type G2
Abstract
In 2001, Berenstein and Zelevinsky presented a polyhedral model for the problem of computing tensor-product multiplicities for semi\-simple Lie algebras. We provide explicit linear equations and inequalities for Berenstein--Zelevinsky (BZ) polytopes of type-G2 Lie algebras. We prove that the denominator of a type-G2 BZ~polytope divides $180$, and that this bound is sharp, while the quasi-period of the Ehrhart quasipolynomial of such a polytope is always a divisor of $6$. We also show that BZ~polytopes of type-G2 Lie algebras can fail to satisfy Ehrhart positivity, in contrast to a conjectured property of BZ~polytopes for all classical types.
Related
- The Zelevinsky involution, co-standard modules for quantum affine algebras and interval symmetric functions
- GORENSTEIN FANO POLYTOPES ARISING FROM ORDER POLYTOPES AND CHAIN POLYTOPES
- SL(n)-covariant symmetric tensor valuations on polytopes
- Quasi-polynomial valuations of lattice polytopes
- Palindromic real-rooted polynomials and h-vectors of polytopes
BibTeX
@misc{magnuson2026berensteinzelevinsky,
title = {{Berenstein-Zelevinsky polytopes for type $\mathrmG_2$}},
author = {Thomas Magnuson and Tyrrell McAllister},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.42038},
eprint = {2610.42038},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.42038},
}
RIS
TY - UNPB
TI - Berenstein-Zelevinsky polytopes for type G_2
AU - Thomas Magnuson
AU - Tyrrell McAllister
PY - 2026
DA - 2026/10/30
PB - arXiv
DO - 10.48550/arxiv.2610.42038
UR - https://arxiv.org/abs/2610.42038
AB - In 2001, Berenstein and Zelevinsky presented a polyhedral model for the problem of computing tensor-product multiplicities for semi\-simple Lie algebras. We provide explicit linear equations and inequalities for Berenstein--Zelevinsky (BZ) polytopes of type-G_2 Lie algebras. We prove that the denominator of a type-G_2 BZ~polytope divides $180$, and that this bound is sharp, while the quasi-period of the Ehrhart quasipolynomial of such a polytope is always a divisor of $6$. We also show that BZ~polytopes of type-G_2 Lie algebras can fail to satisfy Ehrhart positivity, in contrast to a conjectured property of BZ~polytopes for all classical types.
ER -