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Related papers: Units, zero-divisors and idempotents in rings grad…

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We describe the main questions connected to torsion subgroups in the unit group of integral group rings of finite groups and algorithmic methods to attack these questions. We then prove the Zassenhaus Conjecture for Amitsur groups and prove…

Representation Theory · Mathematics 2020-04-09 Andreas Bächle , Wolfgang Kimmerle , Leo Margolis

During the past three decades fundamental progress has been made on constructing large torsion-free subgroups (i.e. subgroups of finite index) of the unit group $\U (\Z G)$ of the integral group ring $\Z G$ of a finite group $G$. These…

Rings and Algebras · Mathematics 2020-08-27 Eric Jespers

We describe and present a new construction method for codes using encodings from group rings. They consist primarily of two types: zero-divisor and unit-derived codes. Previous codes from group rings focused on ideals; for example cyclic…

Information Theory · Computer Science 2007-11-01 Paul Hurley , Ted Hurley

We show that the units found in torsion-free group rings by Gardam are twisted unitary elements. This justifies some choices in Gardam's construction that might have appeared arbitrary, and yields more examples of units. We note that all…

Rings and Algebras · Mathematics 2022-12-23 Laurent Bartholdi

We discuss the decomposability of torsion-free abelian groups. We show that among computable groups of finite rank this property is $\Sigma^0_3$-complete. However, when we consider groups of infinite rank, it becomes $\Sigma^1_1$-complete,…

Logic · Mathematics 2013-11-11 Kyle Riggs

For an acyclic quiver Q, we solve the Clebsch-Gordan problem for the projective representations by computing the multiplicity of a given indecomposable projective in the tensor product of two indecomposable projectives. Motivated by this…

Representation Theory · Mathematics 2013-09-24 Ryan Kinser , Ralf Schiffler

Commutative semirings with divisible additive semigroup are studied. We show that an additively divisible commutative semiring is idempotent, provided that it is finitely generated and torsion. In case that a one-generated additively…

Commutative Algebra · Mathematics 2014-01-14 Tomáš Kepka , Miroslav Korbelář

In this paper, the Identity Problem for certain groups, which asks if the subsemigroup generated by a given finite set of elements contains the identity element, is related to problems regarding ordered groups. Notably, the Identity Problem…

Group Theory · Mathematics 2025-11-26 Corentin Bodart , Laura Ciobanu , George Metcalfe

We show the existence of finitely presented torsion-free groups with decidable word problem that cannot be embedded in any finitely generated group with decidable conjugacy problem. This answers a well-known question of Collins from the…

Group Theory · Mathematics 2019-12-02 Arman Darbinyan

In this paper, we investigate semirings whose elements are either units or zero-divisors (nilpotents) with many examples. While comparing these semirings with their counterparts in ring theory, we observe that their behavior is different in…

Commutative Algebra · Mathematics 2025-07-24 Hussein Behzadipour , Henk Koppelaar , Peyman Nasehpour

We give a uniform construction that, on input of a recursive presentation $P$ of a group, outputs a recursive presentation of a torsion-free group, isomorphic to $P$ whenever $P$ is itself torsion-free. We use this to re-obtain a known…

Group Theory · Mathematics 2016-10-20 Maurice Chiodo

Torsion theories are a pinnacle in the theory of abelian categories. They are a generalization of torsion abelian groups and in this generalization one of the most studied is that whose torsionfree class consists of nonsingular modules. To…

The unit conjecture, commonly attributed to Kaplansky, predicts that if $K$ is a field and $G$ is a torsion-free group then the only units of the group ring $K[G]$ are the trivial units, that is, the non-zero scalar multiples of group…

Group Theory · Mathematics 2021-11-24 Giles Gardam

The separability tensor element of a separable extension of noncommutative rings is an idempotent when viewed in the correct endomorphism ring; so one speaks of a separability idempotent, as one usually does for separable algebras. It is…

Rings and Algebras · Mathematics 2019-08-30 Lars Kadison

Kaplansky Zero Divisor Conjecture states that if $G $ is a torsion free group and $ \mathbb{F} $ is a field, then the group ring $\mathbb{F}[G]$ contains no zero divisor and Kaplansky Unit Conjecture states that if $G $ is a torsion free…

Group Theory · Mathematics 2017-10-17 Alireza Abdollahi , Fatemeh Jafari

We define a class $\mathcal{U}$ of solvable groups of finite abelian section rank which includes all such groups that are virtually torsion-free as well as those that are finitely generated. Assume that $G$ is a group in $\mathcal{U}$ and…

Group Theory · Mathematics 2014-12-30 Karl Lorensen

We develop the theory of groupoid graded semisimple rings. Our rings are neither unital nor one-sided artinian. Instead, they exhibit a strong version of having local units and being locally artinian, and we call them $\Gamma_0$-artinian.…

Rings and Algebras · Mathematics 2025-12-16 Zaqueu Cristiano , Wellington Marques de Souza , Javier Sánchez

This article focuses on the study of cut groups, i.e., the groups which have only trivial central units in their integral group ring. We provide state of art for cut groups. The results are compiled in a systematic manner and have also been…

Rings and Algebras · Mathematics 2025-05-15 Seema Chahal , Sugandha Maheshwary

A nontrivial element in a group is a generalized torsion element if some nonempty finite product of its conjugates is the identity. We prove that any generalized torsion element in a free product of torsion-free groups is conjugate to a…

Geometric Topology · Mathematics 2018-11-20 Tetsuya Ito , Kimihiko Motegi , Masakazu Teragaito

For a finite group $G$ and $U: = U(\mathbb{Z}G)$, the group of units of the integral group ring of $G$, we study the implications of the structure of $G$ on the abelianization $U/U'$ of $U$. We pose questions on the connections between the…

Rings and Algebras · Mathematics 2021-09-01 Andreas Bächle , Sugandha Maheshwary , Leo Margolis