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Related papers: Homotopy of profinite groups

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We prove that every small profinite group can be decomposed into a direct product of indecomposable profinite groups, and that such a decomposition is unique up to order and isomorphisms of the components. We also investigate the…

Group Theory · Mathematics 2024-12-11 Tamar Bar-On , Nikolay Nikolov

Compact connected abelian groups, or protori, have intrinsic structural characteristics that present for the entire category. In the case of finite-dimensional torus-free protori, The Resolution Theorem for Compact Abelian Groups sets the…

Group Theory · Mathematics 2025-03-28 Wayne Lewis

We investigate the ability of a free pro-$\CC$ group of infinite rank to abstractly solve abstract embedding problems, and conclude that for some varieties $\CC$, the profinite completion of any order, of a free pro-$\CC$ group of infinite…

Group Theory · Mathematics 2023-01-31 Tamar Bar-On

Profinite groups with a cyclotomic $p$-orientation are introduced and studied. The special interest in this class of groups arises from the fact that any absolute Galois group $G_{K}$ of a field $K$ is indeed a profinite group with a…

Group Theory · Mathematics 2020-11-10 Claudio Quadrelli , Thomas Weigel

We introduce and investigate a class of profinite groups defined via extensions of centralizers analogous to the extensively studied class of finitely generated fully residually free groups, that is, limit groups (in the sense of Z. Sela).…

Group Theory · Mathematics 2017-11-07 Pavel Zalesskii , Theo Zapata

In this paper we initiate a systematic study of the abstract commensurators of profinite groups. The abstract commensurator of a profinite group $G$ is a group $Comm(G)$ which depends only on the commensurability class of $G$. We study…

Group Theory · Mathematics 2011-07-22 Yiftach Barnea , Mikhail Ershov , Thomas Weigel

We describe free prosoluble subgroups of a free product of profinite groups by strengthening the theorem of Frorian Pop and answering two questions of K. Ersoy and W. Herfort. Relatively projective prosoluble groups are also described.

Group Theory · Mathematics 2024-11-20 Pavel Zalesskii

We study in detail the profinite group G arising as geometric \'etale iterated monodromy group of an arbitrary quadratic polynomial over a field of characteristic different from two. This is a self-similar closed subgroup of the group of…

Group Theory · Mathematics 2013-09-25 Richard Pink

We introduce a notion of a filtered model structure and use this notion to produce various model structures on pro-categories. This framework generalizes several known examples. We give several examples, including a homotopy theory for…

Algebraic Topology · Mathematics 2007-05-23 Halvard Fausk , Daniel C. Isaksen

We investigate accessible subgroups of a profinite group $G$, i.e. subgroups $H$ appearing as vertex groups in a graph of profinite groups decomposition of $G$ with finite edge groups. We prove that any accessible subgroup $H \leq G$ arises…

Group Theory · Mathematics 2024-10-23 Julian Wykowski

Given a profinite group $G$ and a family $\mathcal{F}$ of finite groups closed under taking subgroups, direct products and quotients, denote by $\mathcal{F}(G)$ the set of elements $g \in G$ such that $\{x \in G\ |\ \langle g,x \rangle \…

Group Theory · Mathematics 2025-05-23 Martino Garonzi , Andrea Lucchini , Nowras Otmen

For a prime number $p$ and a free profinite group $S$ on the basis $X$, let $S_{(n,p)}$, $n=1,2,\ldots,$ be the $p$-Zassenhaus filtration of $S$. For $p>n$, we give a word-combinatorial description of the cohomology group…

Number Theory · Mathematics 2020-04-23 Ido Efrat

Zassenhaus filtrations of profinite groups are an important tool to study profinite groups.In this paper, we describe Zassenhaus filtrations of profinite groups as intersections of kernels of certain representations. In this way we…

Group Theory · Mathematics 2025-10-24 Jan Minac , Nguyen Duy Tan , Nguyen Thi Tra

In this article we consider the homotopy theory of stratified spaces through a simplicial point of view. We first consider a model category of filtered simplicial sets over some fixed poset $P$, and show that it is a simplicial…

Algebraic Topology · Mathematics 2020-03-24 Sylvain Douteau

Let $G$ denote a possibly discrete topological group admitting an open subgroup $I$ which is pro-$p$. If $H$ denotes the corresponding Hecke algebra over a field $k$ of characteristic $p$ then we study the adjunction between $H$-modules and…

Representation Theory · Mathematics 2023-03-06 Nicolas Dupré , Jan Kohlhaase

Just infinite groups play a significant role in profinite group theory. For each $c \geq 0$, we consider more generally JNN$_c$F profinite (or, in places, discrete) groups that are Fitting-free; these are the groups $G$ such that every…

Group Theory · Mathematics 2023-09-06 Benjamin Klopsch , Martyn Quick

The article deals with profinite groups in which the centralizers are abelian (CA-groups), that is, with profinite commutativity-transitive groups. It is shown that such groups are virtually pronilpotent. More precisely, let G be a…

Group Theory · Mathematics 2018-07-09 Pavel Shumyatsky , Pavel Zalesskii , Theo Zapata

In this series of three papers, we introduce and study cyclotomic pairs and smooth profinite groups. They are a geometric axiomatisation of Kummer theory for fields, with coefficients $p$-primary roots of unity, for a prime $p$. These…

Algebraic Geometry · Mathematics 2025-03-19 Charles De Clercq , Mathieu Florence

In this paper we consider simplicial families, that is, simplicial objects indexed by a simplicial set. We develop a method to construct family hypercover refinements of a cover family based on the notion of \emph{n-spans} that we introduce…

Category Theory · Mathematics 2017-10-04 Eduardo J. Dubuc

In a previous work, by extending the classical Quillen construction to the non-simply connected case, we have built a pair of adjoint functors, 'model' and 'realization', between the categories of simplicial sets and complete differential…

Algebraic Topology · Mathematics 2018-10-22 Urtzi Buijs , Yves Félix , Aniceto Murillo , Daniel Tanré