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We introduce an equivalence relation on $W^{s,p}({\mathbb S}^N;{\mathbb S}^N)$ involving the topological degree, and we evaluate the distances (in the usual sense and in the Hausdorff sense) between the equivalence classes. In some special…

Functional Analysis · Mathematics 2016-06-16 Haim Brezis , Petru Mironescu , Itai Shafrir

The interdefinability of the universal concepts of category theory has been introduced by Lawvere. The perfect interdefinability between the objects and arrows of some category, defines the class of Perfectly Symmetric Categories (PSC)…

General Mathematics · Mathematics 2026-02-23 Zoran Majkic

Let $\mathcal{C}$ be a small category, $\mathfrak{A}$ be a precosheaf of unital $k$-algebras on $\mathcal{C}$ and $\mathfrak{M}$ be an $\mathfrak{A}$-bimodule. We introduce two new notions, namely, the Grothendieck construction…

Representation Theory · Mathematics 2025-07-29 Mawei Wu

The homotopy theory of small functors is a useful tool for studying various questions in homotopy theory. In this paper, we develop the homotopy theory of small functors from spectra to spectra, and study its interplay with…

Algebraic Topology · Mathematics 2015-11-25 Georg Biedermann , Boris Chorny

We develop some basic concepts in the theory of higher categories internal to an arbitrary $\infty$-topos. We define internal left and right fibrations and prove a version of the Grothendieck construction and of Yoneda's lemma for internal…

Category Theory · Mathematics 2022-04-04 Louis Martini

In arXiv:1711.10132 a new approximating invariant ${\mathsf{TC}}^{\mathcal{D}}$ for topological complexity was introduced called $\mathcal{D}$-topological complexity. In this paper, we explore more fully the properties of…

Algebraic Topology · Mathematics 2018-07-12 Michael Farber , Mark Grant , Gregory Lupton , John Oprea

Invertibility is an important concept in category theory. In higher category theory, it becomes less obvious what the correct notion of invertibility is, as extra coherence conditions can become necessary for invertible structures to have…

Category Theory · Mathematics 2020-10-20 Alex Rice

Algebraic $kk$-theory, introduced by Corti\~nas and Thom, is a bivariant $K$-theory defined on the category $\mathrm{Alg}$ of algebras over a commutative unital ring $\ell$. It consists of a triangulated category $kk$ endowed with a functor…

K-Theory and Homology · Mathematics 2025-12-10 Eugenia Ellis , Emanuel Rodríguez Cirone

We use the ultrafilter-convergence axiomatics for topological spaces to motivate in detail a gentle categorical introduction, first to Barr's Set-based relational T-algebras, and then to Burroni's T-preorders internal to a category C, here…

General Topology · Mathematics 2022-02-22 Amir Homayoun Nejah , Walter Tholen

Building on work by Fiore-Pronk-Paoli, we construct four model structures on the category of double categories, each modeling one of the following: simplicial spaces, Segal spaces, $(\infty,1)$-categories, and $\infty$-groupoids.…

Algebraic Topology · Mathematics 2024-12-23 Léonard Guetta , Lyne Moser

Auslander's formula shows that any abelian category C is equivalent to the category of coherent functors on C modulo the Serre subcategory of all effaceable functors. We establish a derived version of this equivalence. This amounts to…

Category Theory · Mathematics 2015-06-16 Henning Krause

The interleaving distance was originally defined in the field of Topological Data Analysis (TDA) by Chazal et al. as a metric on the class of persistence modules parametrized over the real line. Bubenik et al. subsequently extended the…

Category Theory · Mathematics 2018-06-01 Vin de Silva , Elizabeth Munch , Anastasios Stefanou

Category of fibrant objects is a convenient framework to do homotopy theory, introduced and developed by Ken Brown. In this paper, we apply it to the category of C^{*}-algebras. In particular, we get a unified treatment of (ordinary)…

K-Theory and Homology · Mathematics 2013-03-11 Otgonbayar Uuye

Digital topology is part of the ongoing endeavour to understand and analyze digitized images. With a view to supporting this endeavour, many notions from algebraic topology have been introduced into the setting of digital topology. But some…

Algebraic Topology · Mathematics 2019-05-21 Gregory Lupton , John Oprea , Nicholas Scoville

This article presents a novel approach to construct a model category structure designed to model the homotopy theory of spaces equipped with an action by the group $C_2$, where morphisms are considered to be isovariant. Our methodology…

Algebraic Topology · Mathematics 2023-12-14 Santiago Toro Oquendo

One generally expects that the techniques of arboreal singularities and gluing of local differential graded categories will result in a useful global invariant for all Weinstein manifolds. In this paper we construct explicit models for the…

Symplectic Geometry · Mathematics 2025-11-18 Shanon J. Rubin

In "On o-minimal homotopy groups", o-minimal homotopy was developed for the definable category, proving o-minimal versions of the Hurewicz theorems and the Whitehead theorem. Here, we extend these results to the category of locally…

Logic · Mathematics 2008-12-12 Elias Baro , Margarita Otero

This paper establishes the separation of complexity classes $\mathbf{P}$ and $\mathbf{NP}$ through a novel homological algebraic approach grounded in category theory. We construct the computational category $\mathbf{Comp}$, embedding…

Computational Complexity · Computer Science 2025-12-22 Jian-Gang Tang

We extend the classical theory of homotopical $\Sigma$-sets $\Sigma^n$ developed by Bieri, Neumann, Renz and Strebel for abstract groups, to $\Sigma$-sets $\Sigma_{\mathrm{top}}^n$ for locally compact Hausdorff groups. Given such a group…

Group Theory · Mathematics 2024-10-29 Kai-Uwe Bux , Elisa Hartmann , José Pedro Quintanilha

We introduce new invariants of Hamiltonian fibrations with values in the suitably twisted K-theory of the base. Inspired by techniques of geometric quantization, our invariants arise from the family analytic index of a family of natural…

Symplectic Geometry · Mathematics 2019-01-21 Yasha Savelyev , Egor Shelukhin