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That announcement gives the structure of totally reducible linear Lie algebras which are the Lie algebra of the holonomy group of (at least) one torsion-free connection. The result uses the (already known) classi cation of the irreducible…

Differential Geometry · Mathematics 2013-04-10 Lionel Bérard Bergery

We prove that a uniformly coarsely proper hyperbolic cone over a bounded metric space consisting of a finite union of uniformly coarsely connected components each containing at least two points is non-amenable and apply this to visual…

Metric Geometry · Mathematics 2017-06-06 Juhani Koivisto

Let R be a ring and let G be a group. We prove a rather curious necessary and sufficient condition for the commutative group ring RG to be weakly nil-neat only in terms of R,G and their sections. This somewhat expands three recent results,…

Commutative Algebra · Mathematics 2019-12-17 Peter Danchev , Mahdi Samiei

It is proved that centrally essential rings, whose additive groups of finite rank are torsion-free groups of finite rank, are quasi-invariant but not necessarily invariant. Torsion-free Abelian groups of finite rank with centrally essential…

Rings and Algebras · Mathematics 2020-08-28 Oleg Lyubimtsev , Askar Tuganbaev

Let $A$ be an additively cancellative semialgebra over an additively cancellative semifield $K$ as defined in [9]. For a given partial action $\alpha$ of a group $G$ on an algebra, the associativity of partial skew group ring together with…

Rings and Algebras · Mathematics 2023-06-26 Thakur Meenakshi , R. P. Sharma

We show that an arbitrary algebra ${ A}$, (of arbitrary dimension, over an arbitrary base field and any identity is not suppose for the product), is semisimple if and only if it has zero annihilator and admits a semi-division linear basis.…

Rings and Algebras · Mathematics 2024-10-04 Antonio J. Calderon Martin

We construct in this note a unital properly infinite C*-algebra which is not K$_1$-injective.

Operator Algebras · Mathematics 2016-06-16 Blanchard Etienne

In this paper R will denote a commutative ring with identity and M a nonzero unital R-module. We will generalize the concept of semiannihilator small submodules to the T-semiannihilator small submodules with respect to an arbitrary…

Commutative Algebra · Mathematics 2022-09-01 S. Rajaee , F. Farzalipour , M. Poyan

In this paper we give sufficient conditions for a free product of residually finite groups to admit an embeddable box space. This generalizes the constructions of Arzhantseva, Guentner and Spakula in arXiv:1101.1993v2 and gives a new class…

Group Theory · Mathematics 2018-01-16 Kévin Boucher

In this paper, we introduce the concept of graded m-nil clean ring to extend the existing notion of graded nil-clean ring introduced in [10]. We explore fundamental properties of these rings, emphasizing the interplay between the identity…

Rings and Algebras · Mathematics 2026-05-28 Saikat Das , Sukhendu Kar

We show that there is no theory that is minimal with respect to interpretability among recursively enumerable essentially undecidable theories.

Logic · Mathematics 2022-08-23 Fedor Pakhomov , Juvenal Murwanashyaka , Albert Visser

In line with known results on groups, we show the existence of the nilpotent radical in Lie rings with minimal condition on centralizers. We also prove a form of Engel's theorem if the characteristic is zero.

Logic · Mathematics 2025-03-19 Samuel Zamour

In this note we show that if $G$ is a countably infinite abelian group such that $nG=0$ for some integer $n$, then the only locally minimal group topology on $G$ is the discrete one.

Group Theory · Mathematics 2020-01-01 Dekui Peng

In version v1 (under a different title) I was trying to give a new proof of Wedderburn's Little Theorem (WLT), stating that a finite dision ring is commutative, but I failed. So I had to withdraw the paper (version v2). Firstly I became…

History and Overview · Mathematics 2014-03-20 Leendert Bleijenga

We provide evidence for the Principle : Non-uniruled abelian fibrations are almost non-degenerate.

Algebraic Geometry · Mathematics 2016-04-11 Ying Zong

We prove that the additive group of the rationals does not have an automatic presentation. The proof also applies to certain other abelian groups, for example, torsion-free groups that are $p$-divisible for infinitely many primes $p$, or…

Logic · Mathematics 2009-05-12 Todor Tsankov

We arrange classical small cancellation constructions to produce left-orderable groups: we show that every finitely generated group is the quotient of a left-ordered small cancellation group by a finitely generated kernel (Rips…

Group Theory · Mathematics 2024-01-30 Markus Steenbock

In this work we prove the undecidability (and $\Sigma^0_1$-completeness) of several theories of semirings with fixed points. The generality of our results stems from recursion theoretic methods, namely the technique of effective…

Logic · Mathematics 2025-12-23 Anupam Das , Abhishek De , Stepan L. Kuznetsov

Our main result states that a finite semiring of order >2 with zero which is not a ring is congruence-simple if and only if it is isomorphic to a `dense' subsemiring of the endomorphism semiring of a finite idempotent commutative monoid. We…

Rings and Algebras · Mathematics 2007-05-23 Jens Zumbrägel

We construct the finite-dimensional continuous complex representations of $\mathrm{SL}_2$ over compact discrete valuation rings of even residual characteristic. We also prove that the complex group algebras of $\mathrm{SL}_2$ over finite…

Representation Theory · Mathematics 2023-08-17 M Hassain