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Related papers: A note on strong protomodularity, actions and quot…

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We study the so-called closed and splitting subsemimodules and submodules of a given semimodule or module, respectively. We describe lattices of subsemimodules and of closed subsemimodules and posets of splitting subsemimodules and…

Rings and Algebras · Mathematics 2019-07-16 Ivan Chajda , Helmut Länger

Expansions of abelian categories are introduced. These are certain functors between abelian categories and provide a tool for induction/reduction arguments. Expansions arise naturally in the study of coherent sheaves on weighted projective…

Representation Theory · Mathematics 2010-09-20 Xiao-Wu Chen , Henning Krause

Let $G$ and $A$ be objects of a finitely cocomplete homological category $\mathbb C$. We define a notion of an (internal) action of $G$ of $A$ which is functorially equivalent with a point in $\mathbb C$ over $G$, i.e. a split extension in…

Category Theory · Mathematics 2010-03-02 Manfred Hartl , Bruno Loiseau

In the first part of this paper we study fibrations of $(\infty,2)$-categories. We give a simple characterization of such fibrations in terms of a certain square being a pullback, and apply this to show that in some cases…

Category Theory · Mathematics 2026-02-10 Fernando Abellán , Rune Haugseng , Louis Martini

We define a convenient $\infty$-operad parametrizing modules over commutative algebras in $\infty$-categories.

Category Theory · Mathematics 2014-09-12 Saul Glasman

In this article, we discuss some properties of holomorphic fibrations in the complex analytic setting.

Algebraic Geometry · Mathematics 2025-04-22 Nobuhiro Honda , Jeff Viaclovsky

We establish connections between silting and tilting objects in an abelian category $\mathcal{B}$ and those in a cleft extension $\mathcal{A}$ of $\mathcal{B}$, which provides a method for constructing more silting and tilting objects. Then…

Representation Theory · Mathematics 2026-02-10 Guoqiang Zhao , Juxiang Sun

We study properties of relative modular categories and derive sufficient conditions for their existence. In particular, we derive sufficient conditions for relative pre-modular categories to be non-degenerate and relative modular, and for…

Representation Theory · Mathematics 2021-11-01 Nathan Geer , Bertrand Patureau-Mirand , Matthew Rupert

The work is devoted to the extension groups in the category of functors from a small category to an additive category with an Abelian structure in the sense of Heller. It is constructed a spectral sequence which converges to the extension…

Category Theory · Mathematics 2009-09-28 A. A. Husainov , A. Pancar , M. Yapici

The aim of this article is to investigate internal actions and split extensions in the variety of hoops. We provide a characterization of split extensions with strong section in terms of strong external actions. Beyond the general setting…

Category Theory · Mathematics 2026-03-31 Manuel Mancini , Giuseppe Metere , Federica Piazza

In this short expository note, we discuss, with plenty of examples, the bestiary of fibrations in quasicategory theory. We underscore the simplicity and clarity of the constructions these fibrations make available to end-users of higher…

Category Theory · Mathematics 2016-08-15 Clark Barwick , Jay Shah

The behavior of factorization properties in various ring extensions is a central theme in commutative algebra. Classically, the UFDs are (completely) integrally closed and tend to behave well in standard ring extensions, with the notable…

Commutative Algebra · Mathematics 2025-04-16 Jason Boynton , Jim Coykendall , Grant Moles , Chelsey Morrow

In this paper we study quotients of posets by group actions. In order to define the quotient correctly we enlarge the considered class of categories from posets to loopfree categories: categories without nontrivial automorphisms and…

Category Theory · Mathematics 2007-05-23 Eric Babson , Dmitry N. Kozlov

We introduce the notions of proto-complete, complete, complete* and strong-complete objects in pointed categories. We show under mild conditions on a pointed exact protomodular category that every proto-complete (respectively complete)…

Category Theory · Mathematics 2021-02-22 James Richard Andrew Gray

We argue that various braid group actions on triangulated categories should be extended to projective actions of the category of braid cobordisms and illustrate how this works in examples. We also construct actions of both the affine braid…

Quantum Algebra · Mathematics 2007-07-29 Mikhail Khovanov , Richard Thomas

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

In the last few years, Lopez-Permouth and several collaborators have introduced a new approach in the study of the classical projectivity, injectivity and flatness of modules. This way, they introduced subprojectivity domains of modules as…

Category Theory · Mathematics 2021-03-03 Houda Amzil , Driss Bennis , J. R. Garcia Rozas , Hanane Ouberka , Luis Oyonarte

We review the physical properties of macromolecular networks, consisting of semiflexible polymers such as actin. We start by giving a theoretical analysis of the conformational statistics and mechanical response of single filaments.…

Soft Condensed Matter · Physics 2008-02-03 Erwin Frey , Klaus Kroy , Jan Wilhelm , Erich Sackmann

Characteristic properties of corings with a grouplike element are analysed. Associated differential graded rings are studied. A correspondence between categories of comodules and flat connections is established. A generalisation of the…

Rings and Algebras · Mathematics 2007-05-23 Tomasz Brzezinski

We study algebraic actions of finite groups of quiver automorphisms on moduli spaces of quiver representations. We decompose the fixed loci using group cohomology and we give a modular interpretation of each component. As an application, we…

Algebraic Geometry · Mathematics 2019-09-20 Victoria Hoskins , Florent Schaffhauser