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Bibliographic Details
Main Author: Bianchi, Andrea
Format: Preprint
Published: 2021
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Online Access:https://arxiv.org/abs/2106.09425
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author Bianchi, Andrea
author_facet Bianchi, Andrea
contents We introduce partially multiplicative quandles (PMQ), a generalisation of both partial monoids and quandles. We set up the basic theory of PMQs, focusing on the properties of free PMQs and complete PMQs. For a PMQ $\mathcal{Q}$ with completion $\hat{\mathcal{Q}}$, we introduce the category of $\hat{\mathcal{Q}}$-crossed topological spaces, and define the Hurwitz space $\mathrm{Hur}^Δ(\mathcal{Q})$: it is a $\hat{\mathcal{Q}}$-crossed space, and it parametrises $\mathcal{Q}$-branched coverings of the plane. The definition recovers classical Hurwitz spaces when $\mathcal{Q}$ is a discrete group $G$. Finally, we analyse the class of PMQs $\mathfrak{S}_d^{\mathrm{geo}}$ arising from the symmetric groups $\mathfrak{S}_d$, and we compute their enveloping groups and their PMQ completions.
format Preprint
id arxiv_https___arxiv_org_abs_2106_09425
institution arXiv
publishDate 2021
record_format arxiv
spellingShingle Partially multiplicative quandles and simplicial Hurwitz spaces
Bianchi, Andrea
Algebraic Topology
08A05, 08A35, 18M15, 20B05, 20M05, 55R80
We introduce partially multiplicative quandles (PMQ), a generalisation of both partial monoids and quandles. We set up the basic theory of PMQs, focusing on the properties of free PMQs and complete PMQs. For a PMQ $\mathcal{Q}$ with completion $\hat{\mathcal{Q}}$, we introduce the category of $\hat{\mathcal{Q}}$-crossed topological spaces, and define the Hurwitz space $\mathrm{Hur}^Δ(\mathcal{Q})$: it is a $\hat{\mathcal{Q}}$-crossed space, and it parametrises $\mathcal{Q}$-branched coverings of the plane. The definition recovers classical Hurwitz spaces when $\mathcal{Q}$ is a discrete group $G$. Finally, we analyse the class of PMQs $\mathfrak{S}_d^{\mathrm{geo}}$ arising from the symmetric groups $\mathfrak{S}_d$, and we compute their enveloping groups and their PMQ completions.
title Partially multiplicative quandles and simplicial Hurwitz spaces
topic Algebraic Topology
08A05, 08A35, 18M15, 20B05, 20M05, 55R80
url https://arxiv.org/abs/2106.09425