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It is known that any torsion element in a lambda-ring is nilpotent. In this note we deduce a sharp estimate for the nilpotence degree of such an element.

Commutative Algebra · Mathematics 2010-04-07 F. J. -B. J. Clauwens

We classify nilpotent Lie algebras with complex structures of weakly non-nilpotent type in real dimension eight, which is the lowest dimension where they arise. Our study, together with previous results on strongly non-nilpotent structures,…

Differential Geometry · Mathematics 2025-02-10 A. Latorre , L. Ugarte

An evolution algebra corresponds to a quadratic matrix $A$ of structural constants. It is known the equivalence between nil, right nilpotent evolution algebras and evolution algebras which are defined by upper triangular matrices $A$. We…

Rings and Algebras · Mathematics 2014-11-18 J. M. Casas , M. Ladra , B. A. Omirov , U. A. Rozikov

Let R be a ring with the set of nilpotents Nil(R). We prove that the following are equivalent: (i) Nil(R) is additively closed, (ii) Nil(R) is multiplicatively closed and R satisfies Koethe's conjecture, (iii) Nil(R) is closed under the…

Rings and Algebras · Mathematics 2016-07-11 Janez Šter

We study the algebraic constraints on the structure of nilpotent Lie algebra $\mathbb{g}$, which arise because of the presence of an integrable complex structure $J$. Particular attention is paid to non-abelian complex structures.…

Rings and Algebras · Mathematics 2014-12-02 Dmitry Millionschikov

An element $a$ in a ring $R$ is strongly J-clean if it is the sum of an idempotent and an element in the Jacobson radical that commutes. We characterize the strongly J-clean $2\times 2$ matrices over 2-projective-free non-commutative rings.

Rings and Algebras · Mathematics 2014-10-29 Marjan Sheibani Abdolyousefi , Hunyin Chen , Rahman Bahmani Sangesari

This paper aims to introduce the concept of nilpotency and capability in multiplicative Lie algebras. Also, we see the existence of covers of a multiplicative Lie algebra and thoroughly examine their relationships with capable and perfect…

Group Theory · Mathematics 2023-05-30 Amit Kumar , Mani Shankar Pandey , Sumit Kumar Upadhyay

Let (J,g) be a Hermitian structure on a compact nilmanifold M with invariant complex structure J and compatible metric g, which is not required to be invariant. We give classifications of 6-dimensional nilmanifolds M admitting strong…

Differential Geometry · Mathematics 2007-05-23 Luis Ugarte

We show that a complex structure on a nilpotent almost abelian real Lie algebra is unique if it exists. As a consequence, we get full control over the cohomology and deformations of almost abelian complex nilmanifolds.

Differential Geometry · Mathematics 2025-02-06 Adrián Andrada , Romina M. Arroyo , María L. Barberis , Sönke Rollenske , Konstantin Wehler

In the present context, we investigate to obtain some more results about $2$-nilpotent multiplier $\mathcal{M}^{(2)}(L)$ of a finite dimensional nilpotent Lie algebra $L$. For instance, we characterize the structure of…

Rings and Algebras · Mathematics 2021-05-21 P. Niroomand , M. Parvizi

We study the structure of nilpotent subsemigroups in the semigroup $M(n,\mathbb{F})$ of all $n\times n$ matrices over a field, $\mathbb{F}$, with respect to the operation of the usual matrix multiplication. We describe the maximal…

Group Theory · Mathematics 2010-04-02 Ganna Kudryavtseva , Volodymyr Mazorchuk

This paper explores idempotent and nilpotent operators in bicomplex spaces, focusing on their properties and behavior. We define idempotent and nilpotent matrices in this framework and derive related results. Several theorems are presented…

Representation Theory · Mathematics 2025-09-03 Anjali Anjali , Akhil Prakash , Amita Amita , Neeraj Kumar Tomar

We study the structure of nilpotent completely positive maps in terms of Choi-Kraus coefficients. We prove several inequalities, including certain majorization type inequalities for dimensions of kernels of powers of nilpotent completely…

Operator Algebras · Mathematics 2013-10-03 B V Rajarama Bhat , Nirupama Mallick

In this paper, we present different characterizations of tripotent orthogonal matrices (i.e., A^3 = A = A^* ) in terms of matrix equations, integer powers of AA^* and A^*A, average of A, A^*, and A^{\dagger}, rank of matrices, and trace of…

Rings and Algebras · Mathematics 2025-11-25 Tan Mei , Kezheng Zuo , Wanlin Jiang

We review the known results about characteristically nilpotent complex Lie algebras, as well as we comment recent developements in the theory.

Rings and Algebras · Mathematics 2007-05-23 Jose Maria Ancochea , Otto Rutwig Campoamor

We study the variety of n by n matrices with commutator of rank at most one. We describe its irreducible components; two of them correspond to the pairs of commuting matrices, and n-2 components of smaller dimension corresponding to the…

Representation Theory · Mathematics 2009-03-12 Eliana Zoque

It is well known that n x n upper-triangular real matrices with 1's on the diagonal form a nilpotent Lie group with an interesting family of non-isotropic dilations and corresponding geometry, as in [9]. Here we look at p-adic versions of…

Classical Analysis and ODEs · Mathematics 2012-12-12 Stephen Semmes

We study almost complex structures with lower bounds on the rank of the Nijenhuis tensor. Namely, we show that they satisfy an $h$-principle. As a consequence, all parallelizable manifolds and all manifolds of dimension $2n\geq 10$…

Differential Geometry · Mathematics 2022-10-04 Rui Coelho , Giovanni Placini , Jonas Stelzig

Let $S$ be an additively idempotent semiring and $\mathbf{M}_n(S)$ be the semiring of all $n\times n$ matrices over $S$. We characterize the conditions of when the semiring $\mathbf{M}_n(S)$ is congruence-simple provided that the semiring…

Rings and Algebras · Mathematics 2023-05-02 Tomáš Kepka , Miroslav Korbelář

We prove that in the graded commutative ring $K_{*}(\mathbb{S})$, all positive degree elements are multiplicatively nilpotent. The analogous statements also hold for $TC_{*}(\mathbb{S};\mathbb{Z}^{\wedge}_p)$ and $K_{*}(\mathbb{Z})$.

K-Theory and Homology · Mathematics 2018-03-16 Andrew J. Blumberg , Michael A. Mandell