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We show that there is a functor from the category of positive admissible ternary rings to the category of $*$-algebras, which induces an isomorphism of partially ordered sets between the families of $C^*$-norms on the ternary ring and its…

Operator Algebras · Mathematics 2021-08-12 Fernando Abadie , Damián Ferraro

We prove that an abelian category equipped with an ample sequence of objects is equivalent to the quotient of the category of coherent modules over the corresponding algebra by the subcategory of finite-dimensional modules. In the…

Rings and Algebras · Mathematics 2007-05-23 Alexander Polishchuk

We show that the category of finite-dimensional modules over the endomorphism algebra of a rigid object in a Hom-finite triangulated category is equivalent to the Gabriel-Zisman localisation of the category with respect to a certain class…

Representation Theory · Mathematics 2020-12-21 Aslak Bakke Buan , Bethany Marsh

Let $X$ and $\mathfrak{a}$ be an affine scheme and (respectively) a finite-dimensional associative algebra over an algebraically-closed field $\Bbbk$, both equipped with actions by a linearly-reductive linear algebraic group $G$. We…

Representation Theory · Mathematics 2025-09-03 Alexandru Chirvasitu

We classify the twisted tensor products of a finite set algebra with a two elements set algebra using colored quivers obtained through considerations analogous to Ore extensions. This provides also a classification of entwining structures…

Rings and Algebras · Mathematics 2007-06-17 Claude Cibils

We construct a simple, unital AH algebra which is shape equivalent to its tensor product with any infinite-dimensional UHF algebra, has the same tracial simplex as the said tensor product, and yet is not isomorphic to it. An analogous…

Operator Algebras · Mathematics 2007-05-23 Andrew S. Toms

We describe a logarithmic tensor product theory for certain module categories for a ``conformal vertex algebra.'' In this theory, which is a natural, although intricate, generalization of earlier work of Huang and Lepowsky, we do not…

Quantum Algebra · Mathematics 2008-11-26 Yi-Zhi Huang , James Lepowsky , Lin Zhang

We prove that some subquotient categories of exact categories are abelian. This generalizes a result by Koenig-Zhu in the case of (algebraic) triangulated categories. As a particular case, if an exact category B with enough projectives and…

Representation Theory · Mathematics 2015-09-04 Laurent Demonet , Yu Liu

Following ideas of Lawvere and Linton we prove that classical varieties are precisely the exact categories with a varietal generator. This means a strong generator which is abstractly finite and regularly projective. An analogous…

Category Theory · Mathematics 2024-02-23 Jiri Adamek

We define an action of the braid group (associated with a simple Lie algebra) on the space of $n$-tuples of power series in an indeterminate u, with constant term zero. Using this, we give a sufficient condition for a tensor product of…

Quantum Algebra · Mathematics 2007-05-23 Vyjayanthi Chari

We relate the theory of purity of a locally finitely presented category with products to the study of exact structures on the full subcategory of finitely presented objects. Properties in the context of purity are translated to properties…

Representation Theory · Mathematics 2026-02-16 Kevin Schlegel

We show that Kazhdan and Lusztig's category $KL^k(\mathfrak{sl}_2)$ of modules for the affine Lie algebra $\widehat{\mathfrak{sl}}_2$ at an admissible level $k$, equivalently the category of finite-length grading-restricted generalized…

Quantum Algebra · Mathematics 2025-04-16 Robert McRae , Jinwei Yang

Category theoretic aspects of non-rational conformal field theories are discussed. We consider the case that the category C of chiral sectors is a finite tensor category, i.e. a rigid monoidal category whose class of objects has certain…

High Energy Physics - Theory · Physics 2007-05-23 Jurgen Fuchs

We show that the category O for a rational Cherednik algebra of type A is equivalent to modules over a q-Schur algebra (parameter not a half integer), providing thus character formulas for simple modules. We give some generalization to…

Representation Theory · Mathematics 2007-12-03 Raphael Rouquier

We will study some modifications to the notion of an exact C*-algebra by replacing the minimal tensor product with the reduced free product. First we will demonstrate how the reduced free product of a short exact sequence of C*-algebras…

Operator Algebras · Mathematics 2015-06-05 Paul Skoufranis

Increasingly in recent years, probabilistic computation has been investigated through the lenses of categorical algebra, especially via string diagrammatic calculi. Whereas categories of discrete and Gaussian probabilistic processes have…

Category Theory · Mathematics 2026-05-18 Antonio Lorenzin , Fabio Zanasi

This is the first part in a series of papers in which we introduce and develop a natural, general tensor category theory for suitable module categories for a vertex (operator) algebra. This theory generalizes the tensor category theory for…

Quantum Algebra · Mathematics 2013-05-07 Yi-Zhi Huang , James Lepowsky , Lin Zhang

We present news proofs of the additivity, resolution and cofinality theorems for the algebraic $K$-theory of exact categories. These proofs are entirely algebraic, based on Grayson's presentation of higher algebraic $K$-groups via binary…

K-Theory and Homology · Mathematics 2013-11-21 Tom Harris

We define a unital algebra $A$ over a field $\mathbb{F}$ to be nearly simple if $A$ contains a unique non-trivial ideal $I_A$ such that $I_A^2 \neq \{0\}$. If $A$ and $B$ are two nearly simple algebras, we consider the ideal structure of…

Rings and Algebras · Mathematics 2020-01-01 Ilja Gogić

Let $\hat{R}$ be the $I$-adic completion of a commutative ring $R$ with respect to a finitely generated ideal $I$. We give a necessary and sufficient criterion for the category of perfect complexes over $\hat{R}$ to be equivalent to the…

Commutative Algebra · Mathematics 2024-11-25 Paul Balmer , Beren Sanders