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In [Homotopical Algebra, Springer LNM 43] Quillen introduces the notion of a model category: a category $\mathcal{C}$ provided with three distinguished classes of maps $\{\mathcal{W},\, \mathcal{F},\, co\mathcal{F}\}$ (weak equivalences,…

Category Theory · Mathematics 2020-09-14 Jaqueline Girabel

Category theory in homotopy type theory is intricate as categorical laws can only be stated "up to homotopy", and thus require coherences. The established notion of a univalent category (Ahrens, Kapulkin, Shulman) solves this by considering…

Category Theory · Mathematics 2017-10-31 Paolo Capriotti , Nicolai Kraus

For a (possibly large) realized limit sketch $\mathcal{S}$ such that every $\mathcal{S}$-model is small in a suitable sense we show that the category of cocontinuous functors $\mathsf{Mod}(\mathcal{S}) \to \mathcal{C}$ into a cocomplete…

Category Theory · Mathematics 2023-09-11 Martin Brandenburg

Lifts of categorical diagrams $D\colon\mathsf{J}\to\mathsf{X}$ against discrete opfibrations $\pi\colon\mathsf{E}\to\mathsf{X}$ can be interpreted as presenting solutions to systems of equations. With this interpretation in mind, it is…

Category Theory · Mathematics 2024-01-24 Kevin Arlin , James Fairbanks , Tim Hosgood , Evan Patterson

We first revisit the construction of Quinn's finite total homotopy TQFT, which depends on the choice of a homotopy finite space, $\boldsymbol{B}$. This constitutes a vast generalisation of the Dijkgraaf-Witten TQFT, with a trivial cocycle,…

Category Theory · Mathematics 2025-05-30 João Faria Martins , Timothy Porter

We investigate the triangulated structure of stable monomorphism categories (filtered chain categories) over a Frobenius category. The high degree of symmetry of linear quivers leads to a plethora of semiorthogonal decompositions into…

Category Theory · Mathematics 2026-04-27 Jonas Frank , Mathias Schulze

We consider certain categorical structures that are implicit in subfactor theory. Making the connection between subfactor theory (at finite index) and category theory explicit sheds light on both subjects. Furthermore, it allows various…

Category Theory · Mathematics 2007-05-23 Michael Mueger

Let $X$ be a quasicompact quasiseparated scheme. Write $\operatorname{Gal}(X)$ for the category whose objects are geometric points of $X$ and whose morphisms are specializations in the \'etale topology. We define a natural profinite…

Algebraic Topology · Mathematics 2020-08-25 Clark Barwick , Saul Glasman , Peter Haine

In this paper, we construct incomplete versions of the equivariant stable category; i.e., equivariant stabilization of the category of $G$-spaces with respect to incomplete systems of transfers encoded by an $N_\infty$ operad $\mathcal{O}$.…

Algebraic Topology · Mathematics 2021-02-17 Andrew J. Blumberg , Michael A. Hill

The purpose of this paper is to define equivariant class group of a locally Krull scheme (that is, a scheme which is locally a prime spectrum of a Krull domain) with an action of a flat group scheme, study its basic properties, and apply it…

Commutative Algebra · Mathematics 2013-09-11 Mitsuyasu Hashimoto

This paper is a coalgebra version of arXiv:1703.04266 and a sequel to arXiv:1607.03066. We present the definition of a pseudo-dualizing complex of bicomodules over a pair of coassociative coalgebras $\mathcal C$ and $\mathcal D$. For any…

Category Theory · Mathematics 2022-02-24 Leonid Positselski

Let $U$ be a smooth $\mathbb C$-scheme, $f:U\to\mathbb A^1$ a regular function, and $X=$Crit$(f)$ the critical locus, as a $\mathbb C$-subscheme of $U$. Then one can define the "perverse sheaf of vanishing cycles" $PV_{U,f}$, a perverse…

Algebraic Geometry · Mathematics 2015-06-05 Christopher Brav , Vittoria Bussi , Delphine Dupont , Dominic Joyce , Balazs Szendroi

In the paper we answer the following question: for a morphism of varieties (or, more generally, stacks), when the derived category of the base can be recovered from the derived category of the covering variety by means of descent theory? As…

Algebraic Geometry · Mathematics 2015-05-27 Alexey Elagin

We propose the notion of a supercategory as an alternative approach to supermathematics. We show that this setting is rich to carry out many of the basic constructions of supermathematics. We also prove generalizations of a number of…

Quantum Algebra · Mathematics 2008-02-08 Martin Andler , Siddhartha Sahi

If G is a reductive group which acts on a linearized smooth scheme $X$ then we show that under suitable standard conditions the derived category of coherent sheaves of the corresponding GIT quotient stack $X^{ss}/G$ has a semi-orthogonal…

Algebraic Geometry · Mathematics 2018-01-19 Špela Špenko , Michel Van den Bergh

Given a complete, cocomplete category $\mathcal C$, we investigate the problem of describing those small categories $I$ such that the diagonal functor $\Delta:\mathcal C\to {\rm Functors}(I,\mathcal C)$ is a Frobenius functor. This…

Category Theory · Mathematics 2009-06-04 Alexandru Chirvasitu

For an $(\infty,n)$-category $\mathscr E$ we define an $(\infty,1)$ category $\mathrm{TwAr}(\mathscr E)$ and provide an isomorphism between the stabilization of the overcategory of $\mathscr E$ in $\mathrm{Cat}_{(\infty,n)}$ and the…

Category Theory · Mathematics 2025-04-24 Roman Kositsyn

This paper is concerned with pseudodifferential calculus on manifolds with fibred corners. Following work of Connes, Monthubert, Skandalis and Androulidakis, we associate to every manifold with fibred corners a longitudinally smooth…

Operator Algebras · Mathematics 2013-10-25 Laurent Guillaume

We classify automorphisms on quantum chains, allowing both spin and fermionic degrees of freedom, that are moreover equivariant with respect to a local symmetry action of a finite symmetry group $G$. The classification is up to equivalence…

Mathematical Physics · Physics 2022-01-12 Alex Bols

We investigate Riguet congruences and generalized congruences on a category, focusing on their interrelations from both lattice-theoretic and category-theoretic perspectives. We also characterize functors that are full and surjective on…

Category Theory · Mathematics 2026-05-21 Juan Climent Vidal , Enric Cosme Llópez , Raúl Ruiz Mora