Results 71 to 80 of about 228,669 (269)

Hopfian additive groups of rings [PDF]

Известия Саратовского университета. Новая серия. Серия Математика. Механика. Информатика
A group is called Hopfian  if it is not isomorphic to any of its proper factor groups, or, equivalently, any of its epimorphisms on itself is an isomorphism, i.e., an automorphism. This property was first proved by the Swiss mathematician H.
Kaigorodov, Evgeniy Vladimirovich
doaj   +1 more source

The birational geometry of GIT quotients

Bulletin of the London Mathematical Society, EarlyView.
Abstract Geometric invariant theory (GIT) produces quotients of algebraic varieties by reductive groups. If the variety is projective, this quotient depends on a choice of polarisation; by work of Dolgachev–Hu and Thaddeus, it is known that two quotients of the same variety using different polarisations are related by birational transformations.
Ruadhaí Dervan, Rémi Reboulet
wiley   +1 more source

Abelian JSJ decomposition of graphs of free abelian groups [PDF]

arXiv, 2010
A group G is a vGBS group if it admits a decomposition as a finite graph of groups with all edge and vertex groups finitely generated and free abelian. We construct the JSJ decomposition of a vGBS group over abelian groups. We prove that this decomposition is explicitly computable, and may be obtained by local changes on the initial graph of groups.
arxiv  

Sparse graph signals – uncertainty principles and recovery

GAMM-Mitteilungen, Volume 48, Issue 2, June 2025.
ABSTRACT We study signals that are sparse either on the vertices of a graph or in the graph spectral domain. Recent results on the algebraic properties of random integer matrices as well as on the boundedness of eigenvectors of random matrices imply two types of support size uncertainty principles for graph signals.
Tarek Emmrich, Martina Juhnke, Stefan Kunis   +2 more
wiley   +1 more source

THE DP-RANK OF ABELIAN GROUPS [PDF]

The Journal of Symbolic Logic, 2019
AbstractAn equation to compute the dp-rank of any abelian group is given. It is also shown that its dp-rank, or more generally that of any one-based group, agrees with its Vapnik–Chervonenkis density. Furthermore, strong abelian groups are characterised to be precisely those abelian groups A such that there are only finitely many primes p such that the
Halevi, Yatir, Palacín Cruz, Daniel
openaire   +5 more sources

Tame logarithmic signatures of abelian groups

Journal of Mathematical Cryptology, 2017
The security of the asymmetric cryptosystem MST1{{}_{1}} relies on the hardness of factoring group elements with respect to a logarithmic signature. In this paper we investigate the factorization problem with respect to logarithmic signatures of abelian ...
Reichl Dominik
doaj   +1 more source

On Picent for blocks with normal defect group [PDF]

arXiv, 2020
We prove that if $b$ is a block of a finite group with normal abelian defect group and inertial quotient a direct product of elementary abelian groups, then $\operatorname{Picent}(b)$ is trivial. We also provide examples of blocks $b$ of finite groups with non-trivial $\operatorname{Picent}(b)$.
arxiv  

The Picard group in equivariant homotopy theory via stable module categories

Journal of Topology, Volume 18, Issue 2, June 2025.
Abstract We develop a mechanism of “isotropy separation for compact objects” that explicitly describes an invertible G$G$‐spectrum through its collection of geometric fixed points and gluing data located in certain variants of the stable module category.
Achim Krause
wiley   +1 more source

Conductor of an abelian group

Journal of Algebra, 2009
AbstractLetE(G)=End(G)/N(End(G)). Our goal in this paper is to study direct sum decompositions of certain reduced torsion-free finite rank (rtffr) abelian groups by introducing an ideal τ of E(G) called a conductor of G. This ideal induces a natural ring decomposition E(G)=E(G)(τ)×E(G)τ and a natural direct sum decomposition G=G(τ)⊕Gτ for an rtffr ...
openaire   +2 more sources

c-Regular cyclically ordered groups [PDF]

arXiv, 2013
We define and we characterize regular and c-regular cyclically ordered abelian groups. We prove that every dense c-regular cyclically ordered abelian group is elementarily equivalent to some cyclically ordered group of unimodular complex numbers, that every discrete c-regular cyclically ordered abelian group is elementarily equivalent to some ...
arxiv