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Related papers: Associative algebras and broken lines

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For a given extension $A \subset E$ of associative algebras we describe and classify up to an isomorphism all $A$-complements of $E$, i.e. all subalgebras $X$ of $E$ such that $E = A + X$ and $A \cap X = \{0\}$. Let $X$ be a given…

Rings and Algebras · Mathematics 2014-02-24 A. L. Agore

Let k be an algebraically closed field, let R be an associative k-algebra, and let F = {M_a: a in I} be a family of orthogonal points in R-Mod such that End_R(M_a) = k for all a in I. Then Mod(F), the minimal full sub-category of R-Mod…

Representation Theory · Mathematics 2007-05-23 Eivind Eriksen

Wilcox has considered a twisted semigroup algebra structure on the partition algebra $\mathbb{C}A_k(n)$, but it appears that there has not previously been any known basis that gives $\mathbb{C}A_k(n)$ the structure of a "non-twisted"…

Combinatorics · Mathematics 2025-07-22 John M. Campbell

We develop a new method for analyzing moduli problems related to the stack of pure coherent sheaves on a polarized family of projective schemes. It is an infinite-dimensional analogue of geometric invariant theory. We apply this to two…

Algebraic Geometry · Mathematics 2024-02-05 Daniel Halpern-Leistner , Andres Fernandez Herrero , Trevor Jones

Let X be an algebraic variety with an action of an algebraic group G. Suppose X has a full exceptional collection of sheaves, and these sheaves are invariant under the action of the group. We construct a semiorthogonal decomposition of…

Algebraic Geometry · Mathematics 2015-05-13 Alexei Elagin

In this paper we put forward the definition of particular subsets on a unital C*-algebra, that we call isocones, and which reduce in the commutative case to the set of continuous non-decreasing functions with real values for a partial order…

Operator Algebras · Mathematics 2014-11-18 Fabien Besnard

We derive a formula for the the modular class of a Lie algebroid with a regular twisted Poisson structure in terms of a canonical Lie algebroid representation of the image of the Poisson map. We use this formula to compute the modular…

Symplectic Geometry · Mathematics 2012-12-05 Yvette Kosmann-Schwarzbach , Milen Yakimov

We introduce and investigate a functorial construction which associates coherent sheaves to finite dimensional (restricted) representations of a restricted Lie algebra $\mathfrak g$. These are sheaves on locally closed subvarieties of the…

Algebraic Geometry · Mathematics 2014-08-19 Jon F. Carlson , Eric M. Friedlander , Julia Pevtsova

We introduce the notion of continuous twisted partial actions of a locally compact group on a C*-algebra. With such, we construct an associated C*-algebraic bundle called the semidirect product bundle. Our main theorem shows that, given any…

funct-an · Mathematics 2008-02-03 Ruy Exel

In this survey, we first present basic facts on A-infinity algebras and modules including their use in describing triangulated categories. Then we describe the Quillen model approach to A-infinity structures following K. Lefevre's thesis.…

Representation Theory · Mathematics 2007-05-23 Bernhard Keller

We introduce C-Algebras (quantum analogues of compact Riemann surfaces), defined by polynomial relations in non-commutative variables and containing a real parameter that, when taken to zero, provides a classical non-linear,…

High Energy Physics - Theory · Physics 2009-06-19 J. Arnlind , M. Bordemann , L. Hofer , J. Hoppe , H. Shimada

For an irreducible subvariety Z in an algebraic group G we define a nonnegative integer gdeg(Z) as the degree, in a certain sense, of the Gauss map of Z. It can be regarded as a substitution for the intersection index of the conormal bundle…

Algebraic Geometry · Mathematics 2007-05-23 J. Franecki , M. Kapranov

Building on recent work of Robertson and Steger, we associate a C*-algebra to a combinatorial object which may be thought of as a higher rank graph. This C*-algebra is shown to be isomorphic to that of the associated path groupoid.…

Operator Algebras · Mathematics 2007-05-23 Alex Kumjian , David Pask

It is shown that every $2$-shifted Poisson structure on a finitely generated semi-free commutative differential graded algebra $A$ defines a very explicit infinitesimal $2$-braiding on the homotopy $2$-category of the symmetric monoidal…

Quantum Algebra · Mathematics 2025-03-19 Cameron Kemp , Robert Laugwitz , Alexander Schenkel

To a smooth and proper morphism $\mathcal{X}\to U$ with quasicompact semiseparated target we associate a sheaf in the \'etale topology, which takes an affine $U$-scheme $V$ to the set of $V$-linear semiorthogonal decompositions (of fixed…

Algebraic Geometry · Mathematics 2025-11-17 Pieter Belmans , Shinnosuke Okawa , Andrea T. Ricolfi

We use folding techniques to define a new class of gentle-like algebras that generalise the iterated tilted algebras of type $C$ and $\widetilde{C}$, which we call folded gentle algebras. We then show that folded gentle algebras satisfy…

Representation Theory · Mathematics 2025-03-28 Drew Damien Duffield

Connectivity is a homotopy invariant property of separable C*-algebras which has three notable consequences: absence of nontrivial projections, quasidiagonality and a more geometric realization of KK-theory for nuclear C*-algebras using…

Operator Algebras · Mathematics 2019-10-03 Marius Dadarlat , Ulrich Pennig

For each braided category $\mathcal{C}$ we show that, under mild hypotheses, there is an associated category of "half braided algebras" and their bimodules internal to $\mathcal{C}$ which is not only monoidal but even braided and balanced.…

Quantum Algebra · Mathematics 2026-03-06 Francesco Costantino , Matthieu Faitg

The notion of Poisson manifold with compatible pseudo-metric was introduced by the author in [1]. In this paper, we introduce a new class of Lie algebras which we call a pseudo-Rieamannian Lie algebras. The two notions are strongly related:…

Differential Geometry · Mathematics 2007-05-23 Mohamed Boucetta

We give a new method to construct linear spaces of matrices of constant rank, based on truncated graded cohomology modules of certain vector bundles as well as on the existence of graded Artinian modules with pure resolutions. Our method…

Algebraic Geometry · Mathematics 2017-02-07 Ada Boralevi , Daniele Faenzi , Paolo Lella