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Left-invariant optimal control problems on Lie groups form an important class of problems with big symmetry group. They are interesting from the theoretical point of view since they often can be completely studied, and general features can…

Optimization and Control · Mathematics 2021-05-18 Yuri Sachkov

Pseudorandom binary sequences with optimal balance and autocorrelation have many applications in stream cipher, communication, coding theory, etc. It is known that binary sequences with three-level autocorrelation should have an almost…

Cryptography and Security · Computer Science 2016-02-22 Minglong Qi , Shengwu Xiong , Jingling Yuan , Wenbi Rao , Luo Zhong

In this paper we address the issue of existence of cusp forms for almost simple Lie groups using the approach of the second author combined with local information on supercuspidal representations for $p$-adic groups known by the first…

Number Theory · Mathematics 2013-08-15 Allen Moy , Goran Muic

We study the connectivity of proper power graphs of some family of finite groups including nilpotent groups, groups with a non-trivial partition, and symmetric and alternating groups.

Group Theory · Mathematics 2014-01-28 Alireza Doostabadi , Mohammad Farrokhi Derakhshandeh Ghouchan

Let $S,T$ be two numerical semigroups. We study when $S$ is one half of $T$, with $T$ almost symmetric. If we assume that the type of $T$, $t(T)$, is odd, then for any $S$ there exist infinitely many such $T$ and we prove that $1 \leq t(T)…

Commutative Algebra · Mathematics 2014-04-22 Francesco Strazzanti

Let $G$ be a finite group of Lie type. In studying the cross-characteristic representation theory of $G$, the (specialized) Hecke algebra $H=\End_G(\ind_B^G1_B)$ has played a important role. In particular, when $G=GL_n(\mathbb F_q)$ is a…

Representation Theory · Mathematics 2023-01-19 Jie Du , Brian Parshall , Leonard Scott

In this work we present a new class of numerical semigroups called GSI-semigroups. We see the relations between them and others families of semigroups and we give explicitly their set of gaps. Moreover, an algorithm to obtain all the…

Commutative Algebra · Mathematics 2022-07-28 E. R. García Barroso , J. I. García-García , A. Vigneron-Tenorio

We describe all supergroups with the largest even supersubgroups being isomorphic to $\mathrm{GL}_2, \mathrm{SL}_2$ or $\mathrm{PSL}_2$. These results are applied to the description of centralizers of certain tori in the quasi-reductive…

Representation Theory · Mathematics 2026-03-24 Alexandr N. Zubkov

The categories of almost modules and almost algebras are introduced as a convenient setting for the development of Faltings' method of almost etale extensions. After some preliminaries of general "almost homological algebra" we construct…

Algebraic Geometry · Mathematics 2007-05-23 Ofer Gabber , Lorenzo Ramero

We consider several classes of complete intersection numerical semigroups, aris- ing from many different contexts like algebraic geometry, commutative algebra, coding theory and factorization theory. In particular, we determine all the…

Commutative Algebra · Mathematics 2014-04-08 Marco D'Anna , Vincenzo Micale , Alessio Sammartano

This paper is a continuation of the study on maximal and Frattini L-subgroups of an L-group. The normality of the maximal L-subgroups of a nilpotent L-group is explored. Then, the concept of finitely generated L-subgroup is introduced and…

Group Theory · Mathematics 2025-06-26 Iffat Jahan , Ananya Manas

Two groups are virtually isomorphic if they can be obtained one from the other via a finite number of steps, where each step consists in taking a finite extension or a finite index subgroup (or viceversa). Virtually isomorphic groups are…

Geometric Topology · Mathematics 2016-02-15 Roberto Frigerio

We study quasi-semisimple elements of disconnected reductive algebraic groups over an algebraically closed field. We describe their centralizers, define isolated and quasi-isolated quasi-semisimple elements and classify their conjugacy…

Group Theory · Mathematics 2020-11-23 François Digne , Jean Michel

We construct new examples of non-nil algebras with any number of generators, which are direct sums of two locally nilpotent subalgebras. As all previously known examples, our examples are contracted semigroup algebras and the underlying…

Rings and Algebras · Mathematics 2007-05-23 Vesselin Drensky , Lakhdar Hammoudi

We define a numerical quasi-isometry invariant of a finitely generated group, whose values parametrize the difference between the group being uniformly embeddable in a Hilbert space and the reduced C*-algebra of the group being exact.

Operator Algebras · Mathematics 2007-05-23 Erik Guentner , Jerome Kaminker

A Nash group is said to be almost linear if it has a Nash representation with finite kernel. Structures and basic properties of these groups are studied.

Representation Theory · Mathematics 2013-11-22 Binyong Sun

Symmetries of finite Heisenberg groups represent an important tool for the study of deeper structure of finite-dimensional quantum mechanics. This short contribution presents extension of previous investigations to composite quantum systems…

Mathematical Physics · Physics 2012-04-12 M. Korbelar , J. Tolar

The pro-isomorphic zeta function of a finitely generated nilpotent group $\Gamma$ is a Dirichlet generating function that enumerates finite-index subgroups whose profinite completion is isomorphic to that of $\Gamma$. Such zeta functions…

Group Theory · Mathematics 2016-04-25 Mark N. Berman , Benjamin Klopsch , Uri Onn

Let $D$ be a weakly locally finite division ring and $n$ a positive integer. In this paper, we investigate the problem on the existence of non-cyclic free subgroups in non-central almost subnormal subgroups of the general linear group ${\rm…

Rings and Algebras · Mathematics 2016-02-12 Nguyen Kim Ngoc , Mai Hoang Bien , Bui Xuan Hai

We examine the question of quasidiagonality for C*-algebras of discrete amenable groups from a variety of angles. We give a quantitative version of Rosenberg's theorem via paradoxical decompositions and a characterization of…

Operator Algebras · Mathematics 2013-06-19 José Carrión , Marius Dadarlat , Caleb Eckhardt