The Splitting of Generalisations of the Fadell-Neuwirth short exact sequence

Fuente: arXiv
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Main Authors: Gonçalves, Daciberg Lima, Guaschi, John, Pereiro, Carolina de Miranda e
Format: Preprint
Published: 2025
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author Gonçalves, Daciberg Lima
Guaschi, John
Pereiro, Carolina de Miranda e
author_facet Gonçalves, Daciberg Lima
Guaschi, John
Pereiro, Carolina de Miranda e
contents We study some generalisations to mixed braid groups of the Fadell-Neuwirth short exact sequence and the possible splitting of this sequence. In certain cases, we determine conditions under which the projection from the mixed braid group $B_{n_{1},\ldots,n_{k}}(M)$ to $B_{n_{1},\ldots, n_{k-q}}(M)$ admits a section, where $M$ is either the torus or the Klein bottle, $n_{1}, \ldots, n_{k},q \in \mathbb{N}$, and $1\leq q \leq k-1$. For $k\geq 2$ and $q=k-1$, we show that this projection admits a section if and only if $n_{1}$ divides $n_{i}$ for all $i=2,\ldots, k$. We present some partial conclusions in the case $k\geq 3$ and $q=1$. To obtain our results, we compute and make use of suitable mixed braid groups of $M$, as well as certain key quotients that play a central rôle in our analysis.
format Preprint
id arxiv_https___arxiv_org_abs_2509_02707
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle The Splitting of Generalisations of the Fadell-Neuwirth short exact sequence
Gonçalves, Daciberg Lima
Guaschi, John
Pereiro, Carolina de Miranda e
Geometric Topology
Algebraic Topology
We study some generalisations to mixed braid groups of the Fadell-Neuwirth short exact sequence and the possible splitting of this sequence. In certain cases, we determine conditions under which the projection from the mixed braid group $B_{n_{1},\ldots,n_{k}}(M)$ to $B_{n_{1},\ldots, n_{k-q}}(M)$ admits a section, where $M$ is either the torus or the Klein bottle, $n_{1}, \ldots, n_{k},q \in \mathbb{N}$, and $1\leq q \leq k-1$. For $k\geq 2$ and $q=k-1$, we show that this projection admits a section if and only if $n_{1}$ divides $n_{i}$ for all $i=2,\ldots, k$. We present some partial conclusions in the case $k\geq 3$ and $q=1$. To obtain our results, we compute and make use of suitable mixed braid groups of $M$, as well as certain key quotients that play a central rôle in our analysis.
title The Splitting of Generalisations of the Fadell-Neuwirth short exact sequence
topic Geometric Topology
Algebraic Topology
url https://arxiv.org/abs/2509.02707