English
Related papers

Related papers: Krull-Schmidt categories and projective covers

200 papers

We prove that any fusion category over $\mathbb{C}$ with exactly one non-invertible simple object is spherical. Furthermore, we classify all such categories that come equipped with a braiding.

Quantum Algebra · Mathematics 2011-02-24 Josiah Thornton

We determine versal non-commutative deformations of some simple collections in the categories of perverse coherent sheaves arising from tilting generators for projective morphisms.

Algebraic Geometry · Mathematics 2018-06-14 Yujiro Kawamata

Koszul algebras have arisen in many contexts; algebraic geometry, combinatorics, Lie algebras, non-commutative geometry and topology. The aim of this paper and several sequel papers is to show that for any finite dimensional algebra there…

Category Theory · Mathematics 2014-12-17 Roberto Martinez-Villa , Øyvind Solberg

In nature, one observes that a K-theory of an object is defined in two steps. First a "structured" category is associated to the object. Second, a K-theory machine is applied to the latter category to produce an infinite loop space. We…

K-Theory and Homology · Mathematics 2013-04-03 Nicolas Michel

Colimits are a fundamental construction in category theory. They provide a way to construct new objects by gluing together existing objects that are related in some way. We introduce a complementary notion of anticolimits, which provide a…

Category Theory · Mathematics 2024-01-31 Calin Tataru , Jamie Vicary

Assume that $\D$ is a Krull-Schmidt, Hom-finite triangulated category with a Serre functor and a cluster-tilting object $T$. We introduce the notion of relative cluster tilting objects, and $T[1]$-cluster tilting objects in $\D$, which are…

Representation Theory · Mathematics 2017-03-29 Wuzhong Yang , Bin Zhu

In a perfect category every object has a minimal projective resolution. We give a criterion for the category of modules over a categorygraded algebra to be perfect.

Category Theory · Mathematics 2016-02-09 Ana Paula Santana , Ivan Yudin

We define the concept of a regular object with respect to another object in an arbitrary category. We present basic properties of regular objects and we study this concept in the special cases of abelian categories and locally finitely…

Category Theory · Mathematics 2007-05-23 S. S. Dăscălescu , C. Năstăsescu , A. Tudorache , L. Dăuş

We give an algorithm for working out the indecomposable direct summands in a Krull--Schmidt decomposition of a tensor product of two simple modules for G=SL_3 in characteristics 2 and 3. It is shown that there is a finite family of modules…

Representation Theory · Mathematics 2010-10-26 C. Bowman , S. R. Doty , S. Martin

We show that the quotient of the continuous cluster category $\mathcal C_\pi$ modulo the additive subcategory generated by any cluster is an abelian category and we show that it is isomorphic to the category of infinite length modules over…

Representation Theory · Mathematics 2019-09-13 Kiyoshi Igusa , Gordana Todorov

We present an alternative construction of Soergel's category of bimodules associated to a reflection faithful representation of a Coxeter system. We show that its objects can be viewed as sheaves on the associated moment graph. We introduce…

Representation Theory · Mathematics 2010-06-07 Peter Fiebig

We show that any preadditive infinity category with duality gives rise to a direct sum hermitian K-theory spectrum. This assignment is lax symmetric monoidal, thereby producing E-infinity ring spectra from preadditive symmetric monoidal…

K-Theory and Homology · Mathematics 2025-04-01 Hadrian Heine , Alejo Lopez-Avila , Markus Spitzweck

We review the notions of a multiplier category and the $W^{*}$-envelope of a $C^{*}$-category. We then consider the notion of an orthogonal sum of a (possibly infinite) family of objects in a $C^{*}$-category. Furthermore, we construct…

K-Theory and Homology · Mathematics 2025-12-11 Ulrich Bunke , Alexander Engel

In this paper we continue with the algebraic study of Krivine's realizability, refining some of the authors' previous constructions by introducing two categories, with objects the abstract Krivine structures and the implicative algebras…

Logic · Mathematics 2019-04-19 Walter Ferrer , Octavio Malherbe

This paper introduces the concept of gluing in a general category, enabling us to define categories that admit glued-up objects. To achieve this, we introduce the notion of a gluing index category. Subsequently, we provide an entirely…

Category Theory · Mathematics 2024-03-03 Sophie Marques , Damas Mgani

These notes are meant to provide a rapid introduction to triangulated categories. We start with the definition of an additive category and end with a glimps of tilting theory. Some exercises are included.

K-Theory and Homology · Mathematics 2007-05-23 Behrang Noohi

We define a knot invariant and a 2-knot invariant from any finite categorical group. We calculate an explicit example for the Spun Trefoil.

Geometric Topology · Mathematics 2017-05-23 Joao Faria Martins

The aim of this survey is to present applications of covering techniques in the theory of Krull-Gabriel dimension. We start with recalling fundamental facts of the classical covering theory of quivers and locally bounded categories. Then we…

Representation Theory · Mathematics 2025-03-06 Grzegorz Pastuszak

For a given category B we are interested in studying internal categorical structures in B. This work is the starting point, where we consider reflexive graphs and precategories (i.e., for the purpose of this note, a simplicial object…

Category Theory · Mathematics 2009-03-03 N. Martins-Ferreira

We introduce the notion of a $\textit{reflection fusion category}$, which is a type of a $G$-crossed category generated by objects of Frobenius-Perron dimension $1$ and $\sqrt{p}$, where $p$ is an odd prime. We show that such categories…

Quantum Algebra · Mathematics 2018-04-18 Pavel Etingof , César Galindo