Listar Artículos por departamento/instituto "Álgebra, Geometría y Topología"
Mostrando ítems 1-20 de 34
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A Description of Ad-nilpotent Elements in Semiprime Rings with Involution
Brox-López, José Ramón; García, Esther; Gómez-Lozano, Miguel Ángel
; Muñoz-Alcázar, Rubén José; Vera de Salas, Guillermo (Springer Nature, 2021-07)
In this paper, we study ad-nilpotent elements in Lie algebras arising from semiprime associative rings R free of 2-torsion. With the idea of keeping under control the torsion of R, we introduce a more restrictive notion ... -
A filtration associated to an abelian inner ideal of a Lie algebra.
García González, Esther; Gómez-Lozano, Miguel Ángel; Muñoz-Alcázar, Rubén José (Elsevier, 2022-12-14)
Let B be an abelian inner ideal and let KerL B be the kernel of B. In this paper we show that when there exists n ∈ N with [B,KerL B] n ⊂ B, the inner ideal B induces a bounded filtration in L where B is the first nonzero ... -
A Jordan canonical form for nilpotent elements in an arbitrary ring.
García-González, Esther; Gómez-Lozano, Miguel Ángel; Muñoz-Alcázar, Rubén José; Vera de Salas, Guillermo (Elsevier, 2019)
In this paper we give an inductive new proof of the Jordan canonical form of a nilpotent element in an arbitrary ring. If is a nilpotent element of index n with von Neumann regular , we decompose with a Jordan ... -
Ad-Nilpotent Elements of Skew Index in Semiprime Rings with Involution
Brox-López, José Ramón; García, Esther; Gómez-Lozano, Miguel Ángel; Muñoz-Alcázar, Rubén José; Vera de Salas, Guillermo (Springer Nature, 2022-03)
In this paper, we study ad-nilpotent elements of semiprime rings R with involution * whose indices of ad-nilpotence differ on Skew(R,*) and R. The existence of such an ad-nilpotent element a implies the existence of a GPI ... -
Classification of fiber sequences with a prescribed holonomy action
(Elsevier, 2022-08-01)We define H-fibration sequences as fibrations where the holonomy action of the fundamental group of the base on the fiber lies in a given subgroup H of E(F ), where E(F ) is the homotopy automorphism group of the fiber. ... -
Classification of leavitt path algebras with two vertices
Kanuni, Müge; Martín-Barquero, Dolores; Martín-González, Cándido; Siles-Molina, Mercedes (Independent University of Moscow, 2019-07)
We classify row-finite Leavitt path algebras associated to graphs with no more than two vertices. For the discussion we use the following invariants: decomposability, the K0 group, detpNE1 q (included in the Franks ... -
Contact structures on null hypersurfaces
Atindogbé, Cyriaque; Gutiérrez-López, Manuel; Hounnonkpe, Raymond; Olea, Benjamín (Elsevier, 2022-08)
The aim of this paper is to show how we can induce contact structures, contact metric structures and Sasaki structures on a null hypersurface from a rigging vector field. We give several explicit examples of this construction ... -
Decompositions of endomorphisms into a sum of roots of the unity and nilpotent endomorphisms of fixed nilpotence.
Danchev, Peter; García González, Esther; Gómez-Lozano, Miguel Ángel (Elsevier, 2023-07-10)
For n ≥ 2 and fixed k ≥ 1, we study when an endomorphism f of Fn, where F is an arbitrary field, can be decomposed as t + m where t is a root of the unity endomorphism and m is a nilpotent endomorphism with mk = 0. For ... -
Decompositions of matrices into a sum of invertible matrices and matrices of fixed nilpotence.
Danchev, Peter; García González, Esther; Gómez-Lozano, Miguel Ángel (International Linear Algebra Society, 2023-08-24)
For any n ≥ 2 and fixed k ≥ 1, we give necessary and sufficient conditions for an arbitrary nonzero square matrix in the matrix ring Mn(F) to be written as a sum of an invertible matrix U and a nilpotent matrix N with Nk ... -
Finite sets containing zero are mapping degree sets
Costoya Ramos, María Cristina; Muñoz, Vicente; Viruel-Arbaizar, Antonio Ángel (Elsevier, 2024)
In this paper we solve in the positive the question of whether any finite set of integers, containing 0, is the mapping degree set between two oriented closed connected manifolds of the same dimension. We extend this ... -
Generalized Cesàro operator acting on Hilbert spaces of analytic functions
Mas, Alejandro; Merchán-Álvarez, Noel; De la Rosa, Elena (Springer, 2024-05-14)
Let D denote the unit disc in C. We define the generalized Cesàro operator as follows: Cω( f )(z) = 1 0 f (t z) 1 z z 0 Bω t (u) du ω(t)dt, where {Bω ζ }ζ∈D are the reproducing kernels of the Bergman space ... -
Gradings induced by nilpotent elements.
García González, Esther; Gómez-Lozano, Miguel Ángel; Muñoz-Alcázar, Rubén José; Vera de Salas, Guillermo (Elsevier, 2023)
An element a is nilpotent last-regular if it is nilpotent and its last nonzero power is von Neumann regular. In this paper we show that any nilpotent last-regular element a in an associative algebra R over a ring of scalars ... -
Graph algebras and the Gelfand-Kirillov dimension.
Moreno-Fernández, José Manuel; Siles-Molina, Mercedes (World Scientific Publishing, 2018)
We study some properties of the Gelfand-Kirillov dimension in a non-necessarily unital context. In particular, its Morita invariance when the algebras have local units, and its commutativity with direct limits. We then ... -
Groups as automorphisms of dessins d’enfants
Cañas Muñoz, Alejandro; Hidalgo, Rubén A.; Turiel-Sandín, Francisco Javier; Viruel-Arbaizar, Antonio Ángel (Springer, 2022-08-01)
It is known that every finite group can be represented as the full group of automorphisms of a suitable compact dessin d’enfant. In this paper, we give a constructive and easy proof that the same holds for any countable ... -
Invariant ideals in Leavitt path algebras.
Gil-Canto, Cristóbal; Martín-Barquero, Dolores; Martín-González, Cándido (Universitat Autònoma de Barcelona, Departament de Matemàtiques. Revista: Publications Matematiques, 2020-06-23)
It is known that the ideals of a Leavitt path algebra LK (E) generated by Pl(E), by Pc(E) or by Pec(E) are invariant under isomorphism. Though the ideal generated by Pb∞ (E) is not invariant we find its “natural” replacement ... -
Lie models of homotopy automorphism monoids and classifying fibrations
Félix, Yves; Fuentes Rumí, Mario; Murillo-Mas, Aniceto (Elsevier, 2022-06-25)
Given X a finite nilpotent simplicial set, consider the classifying fibrations X → B aut∗ G(X) → B autG(X) and X → Z → B aut∗ π (X) where G and π denote, respectively, subgroups of the free and pointed homotopy classes ... -
Mackey functors for posets
Carrión Santiago, Guille; Díaz-Ramos, Antonio (Springer Nature, 2025-02-03)
We define Mackey functors over posets mimicking the classical notion and introduce a weak version of them. Then we show that they are acyclic by analyzing cofibrant and pseudoprojective objects in the category of functors ... -
On classical orthogonal polynomials and the Cholesky factorization of a class of Hankel matrices
Marriaga, Misael E.; Vera de Salas, Guillermo; Latorre, Marta; Muñoz-Alcázar, Rubén José (World Scientific Publishing Company, 2024-04)
Classical moment functionals (Hermite, Laguerre, Jacobi, Bessel) can be characterized as those linear functionals whose moments satisfy a second-order linear recurrence relation. In this work, we use this characterization ... -
On Differential Hopf Algebras and B∞ Algebras
Gálvez-Carrillo, Imma; Ronco, María; Tonks, Andrew Peter (Springer Nature, 2025-06-05)
We establish a structure theorem analogous to the classical result of Milnor and Moore: any differential graded (not necessarily co commutative) Hopf algebra H that is cofree as a coalgebra carries an underlying B∞ algebra ... -
On isomorphism conditions for algebra functors with applications to Leavitt Path Algebras
Gil-Canto, Cristóbal; Martín-Barquero, Dolores; Martín-González, Cándido; Ruiz Campos, Iván (Springer, 2023-07)
We introduce certain functors from the category of commu- tative rings (and related categories) to that of Z-algebras (not neces- sarily associative or commutative). One of the motivating examples is the Leavitt path ...