English
Related papers

Related papers: Continuous group actions on profinite spaces

200 papers

One of the major advantages of $\infty$-category theory over classical $1$-category theory is its robust and homotopically meaningful framework for taking (co)limits of diagrams of $\infty$-categories. However, it is both subtle and crucial…

Category Theory · Mathematics 2026-01-15 David Barnes , Niall Taggart

We establish some structural results for the Witt and Grothendieck-Witt groups of schemes over $\mathbb{Z}[1/2]$, including homotopy invariance for Witt groups and a formula for the Witt and Grothendieck-Witt groups of punctured affine…

Algebraic Geometry · Mathematics 2020-09-30 Max Karoubi , Marco Schlichting , Charles Weibel

In this paper we study the category of discrete G-spectra for a profinite group G. We consider an embedding of module objects in spectra into a category of module objects in discrete G-spectra, and study the relationship between the…

Algebraic Topology · Mathematics 2016-09-06 Takeshi Torii

By two well-known results, one of Ax, one of Lubotzky and van den Dries, a profinite group is projective iff it is isomorphic to the absolute Galois group of a pseudo-algebraically closed field. This paper gives an analogous…

Number Theory · Mathematics 2007-05-23 Jochen Koenigsmann

In this paper, we study the actions of profinite groups on Cantor sets which arise from representations of Galois groups of certain fields of rational functions. Such representations are associated to polynomials, and they are called…

Dynamical Systems · Mathematics 2020-05-19 Olga Lukina

Let $k$ be a field with separable closure $\bar{k}\supset k$, and let $X$ be a qcqs $k$-scheme. We use the theory of profinite Galois categories developed by Barwick-Glasman-Haine to provide a quick conceptual proof that the sequences…

Algebraic Topology · Mathematics 2022-12-22 Peter J. Haine , Tim Holzschuh , Sebastian Wolf

Given an abelian $p$-group $G$ of rank $n$, we construct an action of the torus $\mathbb{T}^n$ on the stable module $\infty$-category of $G$-representations over a field of characteristic $p$. The homotopy fixed points are given by the…

Representation Theory · Mathematics 2015-12-08 Akhil Mathew

For every number field and every Cartan Killing type, there is an associated split simple algebraic group. We examine whether the corresponding arithmetic subgroups are profinitely solitary so that the commensurability class of the…

Group Theory · Mathematics 2023-03-20 Holger Kammeyer , Ryan Spitler

The goal of this paper is to prove an equivalence between the model categorical approach to pro-categories, as studied by Isaksen, Schlank and the first author, and the $\infty$-categorical approach, as developed by Lurie. Three…

Algebraic Topology · Mathematics 2017-02-01 Ilan Barnea , Yonatan Harpaz , Geoffroy Horel

We investigate continuous transitive actions of semitopological groups on spaces, as well as separately continuous transitive actions of topological groups.

General Topology · Mathematics 2019-08-15 Jan van Mill , Vesko Valov

We generalize the notions of composition series and composition factors for profinite groups, and prove a profinite version of the Jordan-Holder Theorem. We apply this to prove a Galois Theorem for infinite prosolvable extensions. In…

Group Theory · Mathematics 2025-03-13 Tamar Bar-On , Nikolay Nikolov

We study expansivity and the shadowing property for finitely generated group actions on metric spaces. We consider the projecting and lifting problems for actions having these properties. We prove that every expansive action with the…

Dynamical Systems · Mathematics 2018-12-06 Abdul Gaffar Khan , Pramod Das , Tarun Das

Consider the abelian category ${\mathcal C}$ of commutative group schemes of finite type over a field $k$, its full subcategory ${\mathcal F}$ of finite group schemes, and the associated pro category ${\rm Pro}({\mathcal C})$ (resp. ${\rm…

Algebraic Geometry · Mathematics 2019-05-08 Michel Brion

We study the locus of fixed points of a torus action on a GIT quotient of a complex vector space by a reductive complex algebraic group which acts linearly. We show that, under the assumption that $G$ acts freely on the stable locus, the…

Algebraic Geometry · Mathematics 2026-05-27 Ana-Maria Brecan , Hans Franzen

We study the tensor-triangular geometry of the category of equivariant $G$-spectra for $G$ a profinite group, $\mathsf{Sp}_G$. Our starting point is the construction of a ``continuous'' model for this category, which we show agrees with all…

Algebraic Topology · Mathematics 2024-01-04 Scott Balchin , David Barnes , Tobias Barthel

This paper gives an introduction to homotopy descent, and its applications in algebraic $K$-theory computations for fields. On the \'etale site of a field, a fibrant model of a simplicial presheaf can be constructed from naive Galois…

Algebraic Geometry · Mathematics 2019-06-17 J. F. Jardine

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

In this paper, we examine Lie group actions on moduli spaces (sets themselves built as quotients by group actions) and their fixed points. We show that when the Lie group is compact and connected, we obtain a linear constraint. This…

Representation Theory · Mathematics 2025-01-15 C. J. Lang

We prove that if G is the circle group or a profinite group, then the all of the homotopical information of the category of rational G-spectra is captured by triangulated structure of the rational G-equivariant stable homotopy category.…

Algebraic Topology · Mathematics 2012-01-27 David Barnes , Constanze Roitzheim

We give necessary conditions for a category fibred in pseudo-abelian additive categories over the classifying topos of a profinite group to be a stack; these conditions are sufficient when the coefficients are $\mathbf{Q}$-linear. This…

Algebraic Geometry · Mathematics 2025-06-27 Bruno Kahn