Buildings, valuated matroids, and tropical linear spaces

Fuente: arXiv
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Auteurs principaux: Battistella, Luca, Kuehn, Kevin, Kuhrs, Arne, Ulirsch, Martin, Vargas, Alejandro
Format: Preprint
Publié: 2023
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author Battistella, Luca
Kuehn, Kevin
Kuhrs, Arne
Ulirsch, Martin
Vargas, Alejandro
author_facet Battistella, Luca
Kuehn, Kevin
Kuhrs, Arne
Ulirsch, Martin
Vargas, Alejandro
contents Affine Bruhat--Tits buildings are geometric spaces extracting the combinatorics of algebraic groups. The building of $\mathrm{PGL}$ parametrizes flags of subspaces/lattices in or, equivalently, norms on a fixed finite-dimensional vector space, up to homothety. It has first been studied by Goldman and Iwahori as a piecewise-linear analogue of symmetric spaces. The space of seminorms compactifies the space of norms and admits a natural surjective restriction map from the Berkovich analytification of projective space that factors the natural tropicalization map. Inspired by Payne's result that the analytification is the limit of all tropicalizations, we show that the space of seminorms is the limit of all tropicalized linear embeddings $ι\colon\mathbb{P}^r\hookrightarrow\mathbb{P}^n$ and prove a faithful tropicalization result for compactified linear spaces. The space of seminorms is in fact the tropical linear space associated to the universal realizable valuated matroid.
format Preprint
id arxiv_https___arxiv_org_abs_2304_09146
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Buildings, valuated matroids, and tropical linear spaces
Battistella, Luca
Kuehn, Kevin
Kuhrs, Arne
Ulirsch, Martin
Vargas, Alejandro
Algebraic Geometry
Combinatorics
Affine Bruhat--Tits buildings are geometric spaces extracting the combinatorics of algebraic groups. The building of $\mathrm{PGL}$ parametrizes flags of subspaces/lattices in or, equivalently, norms on a fixed finite-dimensional vector space, up to homothety. It has first been studied by Goldman and Iwahori as a piecewise-linear analogue of symmetric spaces. The space of seminorms compactifies the space of norms and admits a natural surjective restriction map from the Berkovich analytification of projective space that factors the natural tropicalization map. Inspired by Payne's result that the analytification is the limit of all tropicalizations, we show that the space of seminorms is the limit of all tropicalized linear embeddings $ι\colon\mathbb{P}^r\hookrightarrow\mathbb{P}^n$ and prove a faithful tropicalization result for compactified linear spaces. The space of seminorms is in fact the tropical linear space associated to the universal realizable valuated matroid.
title Buildings, valuated matroids, and tropical linear spaces
topic Algebraic Geometry
Combinatorics
url https://arxiv.org/abs/2304.09146