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Related papers: Modified traces and the Nakayama functor

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We provide various ways to characterise $\Sigma$-pure-injective objects in a compactly generated triangulated category. These characterisations mimic analogous well-known results from the model theory of modules. The proof involves two…

Category Theory · Mathematics 2021-03-09 Raphael Bennett-Tennenhaus

Duality properties are studied for a Gorenstein algebra that is finite and projective over its center. Using the homotopy category of injective modules, it is proved that there is a local duality theorem for the subcategory of acyclic…

Rings and Algebras · Mathematics 2022-01-21 Srikanth B. Iyengar , Henning Krause

Buan, Iyama, Reiten and Smith proved that cluster-tilting objects in triangulated 2-Calabi--Yau categories are closely connected with mutation of quivers with potentials over an algebraically closed field. We prove a more general statement…

Representation Theory · Mathematics 2026-04-16 Christoffer Söderberg

Using the Nakayama functor, we construct an equivalence from a Serre quotient category of a category of finitely generated modules to a category of finite-dimensional modules. We then apply this result to the categories FI$_G$ and VI$_q$,…

Representation Theory · Mathematics 2017-10-17 Wee Liang Gan , Liping Li , Changchang Xi

In this paper we introduce a generalization of the Nakayama functor for finite-dimensional algebras. This is obtained by abstracting its interaction with the forgetful functor to vector spaces. In particular, we characterize the Nakayama…

Category Theory · Mathematics 2019-07-22 Sondre Kvamme

For a rigid object $M$ in an algebraic triangulated category $\mathcal{T}$, a functor pr$(M)\to\mathcal{H}^{[-1,0]}({\rm proj}\, A)$ is constructed, which essentially takes an object to its `presentation', where pr$(M)$ is the full…

Representation Theory · Mathematics 2025-09-11 Dong Yang

A variant of the trace in a monoidal category is given in the setting of closed monoidal derivators, which is applicable to endomorphisms of fiberwise dualizable objects. Functoriality of this trace is established. As an application, an…

Category Theory · Mathematics 2019-06-10 Martin Gallauer

We study the extended module category $m\operatorname{-mod}\Lambda$ of an algebra $\Lambda$, recently introduced by Gupta and Zhou. The existence of a postprojective component of $m\operatorname{-mod}\Lambda$ is shown for certain algebras…

Representation Theory · Mathematics 2026-01-22 Endre Sørmo Rundsveen

We consider a class of infinite weighted metric trees obtained as perturbations of self-similar regular trees. Possible definitions of the boundary traces of functions in the Sobolev space on such a structure are discussed by using…

Mathematical Physics · Physics 2025-09-29 Valentina Franceschi , Kiyan Naderi , Konstantin Pankrashkin

Enomoto showed for finite dimensional algebras that the classification of exact structures on the category of finitely generated projective modules can be reduced to the classification of 2-regular simple modules. In this article, we give a…

Combinatorics · Mathematics 2020-07-15 Rene Marczinzik , Martin Rubey , Christian Stump

Given a Henselian and Japanese discrete valuation ring $A$ and a flat and projective $A$-scheme $X$, we follow the approach of Biswas-dos Santos to introduce a full subcategory of coherent modules on $X$ which is then shown to be Tannakian.…

Algebraic Geometry · Mathematics 2019-04-25 Phung Ho Hai , Joao Pedro dos Santos

We give a proof of a formula for the trace of self-braidings (in an arbitrary channel) in UMTCs which first appeared in the context of rational conformal field theories (CFTs). The trace is another invariant for UMTCs which depends only on…

Category Theory · Mathematics 2017-09-14 Luca Giorgetti , Karl-Henning Rehren

We define the functor $\textrm{ncDef}_{(Z_1,\ldots,Z_n)}$ of non-commutative deformations of an $n$-tuple of objects in an arbitrary $k$-linear abelian category $\mathcal{Z}$. In our categorified approach, we view the underlying spaces of…

Algebraic Geometry · Mathematics 2025-05-19 Agnieszka Bodzenta , Alexey Bondal

Using the Nakayama duality induced by a Nakayama functor, we provide a novel and concise account of the existence of Auslander-Reiten dualities and almost split sequences in abelian categories with enough projective objects or enough…

Representation Theory · Mathematics 2025-12-25 Zetao Lin , Shiping Liu

We give criteria for when finitely generated local modules over a commutative algebra $A$ in the ind-completion $\widehat{\mathcal{C}}$ of a braided tensor category $\mathcal{C}$ inherit the structure of a (rigid, braided, ribbon) tensor…

Quantum Algebra · Mathematics 2026-03-31 Kenichi Shimizu , Harshit Yadav

We systematically develop the theory of definable functors between compactly generated triangulated categories. Such functors preserve pure triangles, pure injective objects, and definable subcategories, and as such appear in a wide range…

Category Theory · Mathematics 2025-03-03 Isaac Bird , Jordan Williamson

We introduce Nakayama functors for coalgebras and investigate their basic properties. These functors are expressed by certain (co)ends as in the finite case discussed by Fuchs, Schaumann, and Schweigert. This observation allows us to define…

Quantum Algebra · Mathematics 2023-03-21 Taiki Shibata , Kenichi Shimizu

Let $C$ be an additive category with cokernels and let Mod($C$) be the category of additive functors from $C^{op}$ to the category Ab of abelian groups. Let mod($C$) be the full subcategory of Mod($C$) consisting of coherent functors. In…

Category Theory · Mathematics 2020-12-16 Mohammad Khazaei , Reza Sazeedeh

For certain roots of unity, we consider the categories of weight modules over three quantum groups: small, un-restricted and unrolled. The first main theorem of this paper is to show that there is a modified trace on the projective modules…

Quantum Algebra · Mathematics 2017-10-25 Nathan Geer , Bertrand Patureau-Mirand

We call a finite dimensional algebra A S-connected if the projective dimensions of the simple A-modules form an interval. We prove that a Nakayama algebra A is S-connected if and only if A is quasi-hereditary. We apply this result to…

Representation Theory · Mathematics 2021-09-16 René Marczinzik , Emre Sen