Results 1 to 10 of about 2,732,155 (328)

Squarefree Vertex Cover Algebras [PDF]

Communications in Algebra, 2013
In this paper we introduce squarefree vertex cover algebras. We study the question when these algebras coincide with the ordinary vertex cover algebras and when these algebras are standard graded. In this context we exhibit a duality theorem for squarefree vertex cover algebras.
Shamila Bayati, Farhad Rahmati
openaire   +5 more sources

Homogeneous orthocomplete effect algebras are covered by MV-algebras [PDF]

Fuzzy Sets and Systems, 2013
The aim of our paper is twofold. First, we thoroughly study the set of meager elements Mea(E) and the set of hypermeager elements HMea(E) in the setting of homogeneous effect algebras E. Second, we study the property (W+) and the maximality property introduced by Tkadlec as common generalizations of orthocomplete and lattice effect algebras.
Josef Niederle, Jan Paseka
  +7 more sources

Covering and gluing of algebras and differential algebras [PDF]

Journal of Geometry and Physics, 2000
Extending work of Budzynski and Kondracki, we investigate coverings and gluings of algebras and differential algebras. We describe in detail the gluing of two quantum discs along their classical subspace, giving a C*-algebra isomorphic to a certain Podles sphere, as well as the gluing of U_{\sqrt{q}}(sl_2)-covariant differential calculi on the discs.
R. Matthes, Dirk Calow
openaire   +4 more sources

Covering algebras II: Isomorphism of loop algebras [PDF]

Journal für die reine und angewandte Mathematik (Crelles Journal), 2004
This paper studies the loop algebras that arise from pairs consisting of a symmetrizable Kac-Moody Lie algebra $\g$ and a finite order automorphism $ $ of $\g$. We obtain necessary and sufficient conditions for two such loop algebras to be isomorphic.
Arturo Pianzola, Stephen Berman, Bruce Allison   +2 more
openaire   +3 more sources

A Characterisation of Morita Algebras in Terms of Covers [PDF]

Algebras and Representation Theory, 2021
AbstractA pair (A, P) is called a cover of EndA(P)op if the Schur functor HomA(P,−) is fully faithful on the full subcategory of projective A-modules, for a given projective A-module P. By definition, Morita algebras are the covers of self-injective algebras and then P is a faithful projective-injective module.
openaire   +5 more sources

Special triple covers of algebraic surfaces

Documenta Mathematica, 2022
We study special triple covers f:T\to S of algebraic surfaces, where the Tschirnhausen bundle \mathcal{E}=\left(f_*\mathcal{O}_T/\mathcal{O}_S\right)^\vee is a quotient of a split rank three vector bundle, and we provide several ...
Istrati, Nicolina, Pokora, Piotr, Rollenske, Sönke   +2 more
openaire   +2 more sources

𝐶*-algebras associated with branched coverings [PDF]

Proceedings of the American Mathematical Society, 2000
In this note we analyze the C ∗ C^{\ast } -algebra associated with a branched covering both as a groupoid C ∗ C^{\ast } -algebra and as a Cuntz-Pimsner algebra. We determine conditions when the algebra is simple and purely infinite.
Valentin Deaconu, Paul S. Muhly
openaire   +3 more sources

Coverings of laura algebras: The standard case

Journal of Algebra, 2010
The main result on the non-standard case was reformulated due to an inaccuracy in the previous version. Lemma 6.1 was removed due to a simplification. The last section on the special biserial case was removed. Typos corrected and bibliography updated.
Assem, Ibrahim, Bustamante, Juan Carlos, Le Meur, Patrick   +2 more
openaire   +4 more sources

Covering Morphisms in Categories of Relational Algebras [PDF]

Applied Categorical Structures, 2013
In this paper we use Janelidze’s approach to the classical theory of topological coverings via categorical Galois theory to study coverings in categories of relational algebras. Moreover, we present characterizations of effective descent morphisms in the categories of M-ordered sets and of multi-ordered sets.
M. M. Clementino, D. Hofmann, A. Montoli
openaire   +4 more sources

Covering Algebras I. Extended Affine Lie Algebras

Journal of Algebra, 2002
Covering Algebras of extended affine Lie algebras(EALA's) relative to finite order automorphisms are studied. Conditions are given for when the resulting algebra is again an EALA. This paper deals with affinizations of EALA's relative to finite order automorphisms and these algebras are generalizations of the affine Kac-Moody Lie algebras.
Bruce Allison, Arturo Pianzola, Stephen Berman   +2 more
openaire   +3 more sources