Topological posets and tropical phased matroids

Fuente: arXiv
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Main Authors: Alvarez, Ulysses, Geoghegan, Ross
Format: Preprint
Published: 2021
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author Alvarez, Ulysses
Geoghegan, Ross
author_facet Alvarez, Ulysses
Geoghegan, Ross
contents For a discrete poset $\mathcal X$ McCord proved that the natural map $|{\mathcal X}|\to {\mathcal X}$ from the order complex to the poset equipped with the Up topology is a weak homotopy equivalence. Much later, Zivaljević defined the notion of order complex for a topological poset. For a large class of such topological posets we prove the analog of McCord's theorem, namely that the natural map from the order complex to the topological poset with the Up topology is a weak homotopy equivalence. A familiar topological example is the Grassmann poset of proper non-zero linear subspaces of R^{n+1} partially ordered by inclusion. But our motivation in topological combinatorics is to apply the theorem to posets associated with tropical phased matroids over the tropical phase hyperfield, and in particular to elucidate the tropical version of the MacPhersonian Conjecture. This is explained in Section 2.
format Preprint
id arxiv_https___arxiv_org_abs_2106_09753
institution arXiv
publishDate 2021
record_format arxiv
spellingShingle Topological posets and tropical phased matroids
Alvarez, Ulysses
Geoghegan, Ross
Combinatorics
54F05, 52B40, 14T10, 54F35
For a discrete poset $\mathcal X$ McCord proved that the natural map $|{\mathcal X}|\to {\mathcal X}$ from the order complex to the poset equipped with the Up topology is a weak homotopy equivalence. Much later, Zivaljević defined the notion of order complex for a topological poset. For a large class of such topological posets we prove the analog of McCord's theorem, namely that the natural map from the order complex to the topological poset with the Up topology is a weak homotopy equivalence. A familiar topological example is the Grassmann poset of proper non-zero linear subspaces of R^{n+1} partially ordered by inclusion. But our motivation in topological combinatorics is to apply the theorem to posets associated with tropical phased matroids over the tropical phase hyperfield, and in particular to elucidate the tropical version of the MacPhersonian Conjecture. This is explained in Section 2.
title Topological posets and tropical phased matroids
topic Combinatorics
54F05, 52B40, 14T10, 54F35
url https://arxiv.org/abs/2106.09753