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Let $\pi_1(C)$ be the fundamental group of a smooth irreducible affine curve $C$ over an algebraically closed field of positive characteristic. It is shown that given an embedding problem for $\pi_1(C)$ there exist an open index $p$ normal…

Algebraic Geometry · Mathematics 2010-01-06 Manish Kumar

We give a moduli-theoretic proof of the classical theorem of Gabriel, stating that a scheme can be reconstructed from the abelian category of quasi-coherent sheaves over it. The methods employed are elementary and allow us to extend the…

Algebraic Geometry · Mathematics 2013-10-25 John Calabrese , Michael Groechenig

The first part of the paper centers in the study of embeddability between partially commutative groups. In [KK], for a finite simplicial graph $\Gamma$, the authors introduce an infinite, locally infinite graph $\Gamma^e$, called the…

Group Theory · Mathematics 2015-06-11 Montserrat Casals-Ruiz

We define the notion of a $G$-structure for elliptic curves, where $G$ is a finite 2-generated group. When $G$ is abelian, a $G$-structure is the same as a classical congruence level structure. There is a natural action of…

Number Theory · Mathematics 2017-09-11 William Yun Chen

The moduli space and generalised global symmetries of 3d $\mathcal{N} = 5$ superconformal field theories are investigated, with a focus on the orthosymplectic ABJ theories and their discrete gauging variants. We extend the known…

High Energy Physics - Theory · Physics 2026-03-25 Sebastiano Garavaglia , William Harding , Deshuo Liu , Noppadol Mekareeya

Let $\Gamma$ be a finitely generated cocompact lattice of a totally disconnected locally compact group $G$, and $C$ a dense subgroup of $G$ that contains and commensurates $\Gamma$. We study the problem of describing all finitely generated…

Group Theory · Mathematics 2026-04-08 Adrien Le Boudec , Colin Reid

In this paper, we study $(\varphi,\Gamma)$-modules over rings which are "combinations of discrete algebras and affinoid $\mathbb{Q}_p$-algebras", and prove basic results such as the existence of a fully faithful functor from the category of…

Number Theory · Mathematics 2026-01-30 Yutaro Mikami

The notion of formal Siegel modular forms for an arithmetic subgroup $\Gamma$ of the symplectic group of genus $n$ is a generalization of symmetric formal Fourier-Jacobi series. Assuming an upper bound on the affine covering number of the…

Number Theory · Mathematics 2024-07-09 Jan Hendrik Bruinier , Martin Raum

Let $G$ be a simple algebraic group over an algebraically closed field $k$ and let $C_1, \ldots, C_t$ be non-central conjugacy classes in $G$. In this paper, we consider the problem of determining whether there exist $g_i \in C_i$ such that…

Group Theory · Mathematics 2020-04-13 Timothy C. Burness , Spencer Gerhardt , Robert M. Guralnick

In this paper we explore the structure and properties of C-groups. We define a C-group as a group $G$ with $rk(G) < rk(Z(G))$ (where $rk(G)$ is the minimal cardinal of a generating set for a group $G$). Using GAP (a group theory program)…

Group Theory · Mathematics 2007-05-23 Mihai Tohaneanu , Margarethe Flanders , Avi Silterra

Apart from global topological problems an affine homogeneous space is locally described by its curvature, its torsion and a slightly less tangible object called its connection in a given base point. Using this description of the local…

Differential Geometry · Mathematics 2017-07-21 Gregor Weingart

Let $\Gamma=(\mathcal{V},\mathcal{E})$ be a graph, whose vertices $v\in \mathcal{V}$ are colored black and white and labeled with invertible elements $\lambda_v$ from a commutative and associative ring $R$ containing $\pm 1$. Then we…

Rings and Algebras · Mathematics 2026-04-02 Hans Cuypers

We study to what extent group $C^\ast$-algebras are characterized by their unitary groups. A complete characterization of which Abelian group $C^\ast$-algebras have isomorphic unitary groups is obtained. We compare these results with other…

Operator Algebras · Mathematics 2011-11-09 Jorge Galindo , Ana-Mar'ia R'odenas

Let $\Lambda$ be a basic finite dimensional algebra over an algebraically closed field, presented as a path algebra modulo relations; further, assume that $\Lambda$ is graded by lengths of paths. The paper addresses the classifiability, via…

Representation Theory · Mathematics 2014-07-11 E. Babson , B. Huisgen-Zimmermann , R. Thomas

We investigate whether the group algebra of a finite group over a localisation of the integers is semiperfect. The main result is a necessary and sufficient arithmetic criterion in the ordinary case. In the modular case, we propose a…

Rings and Algebras · Mathematics 2025-10-10 Dylan Johnston , Dmitriy Rumynin

Let $S$ be a reduced $E$-Fountain semigroup. If $S$ satisfies the congruence condition, there is a natural construction of a category $\mathcal{C}$ associated with $S$. We define a $\Bbbk$-module homomorphism $\varphi:\Bbbk…

Representation Theory · Mathematics 2021-11-09 Itamar Stein

A discrete group $\Gamma$ is called exact if the reduced group C*-algebra ${C_{\lambda}}^{*}(\Gamma)$ is exact as C*-algebras, and a discrete group $\Lambda$ is called residually exact if every nonunital element $g \in \Lambda$ admits a…

Group Theory · Mathematics 2025-12-16 Hikaru Awazu

We introduce and investigate new invariants on the pair of modules $M$ and $N$ over quantum affine algebras $U_q'(\mathfrak{g})$ by analyzing their associated R-matrices. From new invariants, we provide a criterion for a monoidal category…

Representation Theory · Mathematics 2020-09-30 Masaki Kashiwara , Myungho Kim , Se-jin Oh , Euiyong Park

We generalize the notion of semi-normalized classes of systems of differential equations, study properties of such classes and extend the algebraic method of group classification to them. In particular, we prove the important theorems on…

Mathematical Physics · Physics 2024-09-02 Celestin Kurujyibwami , Dmytro R. Popovych , Roman O. Popovych

In this article, we provide an explicit description of the Lipschitz saturation $A^*_{B,R}$ of a subalgebra $A\subseteq R[[t^{\gamma_1},\ldots, t^{\gamma_n}]]$ over a ring $R$ in terms of the numerical semigroup $\Gamma =…

Commutative Algebra · Mathematics 2024-11-27 Anne Frühbis-Krüger , Thiago da Silva