Grothendieck Weights on Permutohedral Varieties and Matroids

Fuente: arXiv
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Auteur principal: Wang, Yiyu
Format: Preprint
Publié: 2026
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author Wang, Yiyu
author_facet Wang, Yiyu
contents Grothendieck weights, introduced by Shah, are $K$-theoretic analogues of Minkowski weights on smooth toric varieties. We study Grothendieck weights on the permutohedral fan and prove two main results: a $K$-balancing condition that characterizes Grothendieck weights by a finite system of linear equations, and an explicit product rule for the ring structure. We apply this framework to matroids, giving a combinatorial characterization of Grothendieck weights on matroidal fans. As the main application, we compute the motivic Chern class of the hyperplane arrangement complement in its wonderful compactification and show that the result depends only on the matroid, not on the realization. This allows us to extend the definition of the motivic Chern class to all loopless matroids.
format Preprint
id arxiv_https___arxiv_org_abs_2605_09762
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Grothendieck Weights on Permutohedral Varieties and Matroids
Wang, Yiyu
Algebraic Geometry
Combinatorics
Grothendieck weights, introduced by Shah, are $K$-theoretic analogues of Minkowski weights on smooth toric varieties. We study Grothendieck weights on the permutohedral fan and prove two main results: a $K$-balancing condition that characterizes Grothendieck weights by a finite system of linear equations, and an explicit product rule for the ring structure. We apply this framework to matroids, giving a combinatorial characterization of Grothendieck weights on matroidal fans. As the main application, we compute the motivic Chern class of the hyperplane arrangement complement in its wonderful compactification and show that the result depends only on the matroid, not on the realization. This allows us to extend the definition of the motivic Chern class to all loopless matroids.
title Grothendieck Weights on Permutohedral Varieties and Matroids
topic Algebraic Geometry
Combinatorics
url https://arxiv.org/abs/2605.09762