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Related papers: Classification theory for accessible categories

200 papers

We introduce and study the Scott adjunction, relating accessible categories with directed colimits to topoi. Our focus is twofold, we study both its applications to formal model theory and its geometric interpretation. From the geometric…

Category Theory · Mathematics 2020-09-17 Ivan Di Liberti

Homotopy limits and colimits are homotopical replacements for the usual limits and colimits of category theory, which can be approached either using classical explicit constructions or the modern abstract machinery of derived functors. Our…

Algebraic Topology · Mathematics 2009-07-01 Michael Shulman

Using methods from coarse topology we show that fundamental classes of closed enlargeable manifolds map non-trivially both to the rational homology of their fundamental groups and to the K-theory of the corresponding reduced C*-algebras.…

Algebraic Topology · Mathematics 2018-11-28 B. Hanke , D. Kotschick , J. Roe , T. Schick

We give a new description of computads for weak globular $\omega$-categories by giving an explicit inductive definition of the free words. This yields a new understanding of computads, and allows a new definition of $\omega$-category that…

Category Theory · Mathematics 2024-11-06 Christopher J. Dean , Eric Finster , Ioannis Markakis , David Reutter , Jamie Vicary

The cofinality quantifiers were introduced by Shelah as an example of a compact logic stronger than first-order logic. We show that the classes of models axiomatized by these quantifiers can be turned into an Abstract Elementary Class by…

Logic · Mathematics 2025-04-16 Will Boney

We prove a version of Shelah's Categoricity Conjecture for arbitrary deconstructible classes of modules. Moreover, we show that if $\mathcal{A}$ is a deconstructible class of modules that fits in an abstract elementary class…

Representation Theory · Mathematics 2024-10-01 Jan Šaroch , Jan Trlifaj

We investigate the local topological structure of non-metrizable topological groups through the lens of Tukey order and cofinal types. Motivated by recent advances in topological groups admitting an $\omega^\omega$-base, we introduce the…

General Topology · Mathematics 2026-05-26 Xuan Gong , Dekui Peng

Let $\mathcal A$ be a Hom-finite abelian category with enough projectives. In this note, we show that any covariantly finite $\tau$-rigid subcategory is contained in a support $\tau$-tilting subcategory. We also show that support…

Representation Theory · Mathematics 2023-02-07 Yu Liu , Panyue Zhou

Abstract. We provide a characterization of classes of filters $\mathbb{D}$ for which the full subcategory $\operatorname{fix}\operatorname{A}_{\mathbb D}$ of $\mathsf{Conv}$ formed by convergences determined by the adherence of filters of…

General Topology · Mathematics 2025-04-23 Frédéric Mynard , Jerzy Wojciechowski

We give criteria for subcategories of a compactly generated algebraic triangulated category to be precovering or preenveloping. These criteria are formulated in terms of closure conditions involving products, coproducts, directed homotopy…

Representation Theory · Mathematics 2020-07-15 Rosanna Laking , Jorge Vitória

We provide a short proof of Shelah's eventual categoricity conjecture, assuming the Generalized Continuum Hypothesis ($GCH$), for abstract elementary classes (AEC's) with interpolation, a strengthening of amalgamation which is a necessary…

Logic · Mathematics 2020-12-29 Christian Espíndola

We extend Mazzola's counterpoint model using category theory, generalizing from the category $\mathbf{Set}$ to other topoi with suitable properties. This generalization suggests that counterpoint's essential structure depends on specific…

Category Theory · Mathematics 2026-01-06 Octavio A. Agustín-Aquino , Juan Sebastián Arias , Enrique Ruiz Hernández

This paper explores the interplay between category theory, topology, and the algebraic theory of finite groups. Our analysis unfolds in three stages. First, we establish the foundational universe of our objects: the complete and cocomplete…

Category Theory · Mathematics 2026-03-02 Ismael Gutierrez Garcia , Luz Adriana Mejía Castaño

Coherence is here demonstrated for sesquicartesian categories, which are categories with nonempty finite products and arbitrary finite sums, including the empty sum, where moreover the first and the second projection from the product of the…

Category Theory · Mathematics 2007-05-23 K. Dosen , Z. Petric

Categorical structures and their pseudomaps rarely form locally presentable 2-categories in the sense of Cat-enriched category theory. However, we show that if the categorical structure in question is sufficiently weak (such as the…

Category Theory · Mathematics 2022-01-31 John Bourke

Amenable groups are those admitting an invariant mean -- a finitely additive probability mean that assigns equal ``weight'' to any two translates of the same set. We introduce coset correct means (CCMs), a class of finitely additive means…

Group Theory · Mathematics 2026-04-21 Armando Martino , Motiejus Valiunas

Using generalized enriched categories, in this paper we show that Rosick\'{y}'s proof of cartesian closedness of the exact completion of the category of topological spaces can be extended to a wide range of topological categories over…

Category Theory · Mathematics 2019-05-02 Maria Manuel Clementino , Dirk Hofmann , Willian Ribeiro

One of the main prerequisites for understanding sheaves on elementary toposes is the proof that a (Lawvere-Tierney) topology on a topos induces a closure operator on it, and vice-versa. That standard theorem is usually presented in a…

Category Theory · Mathematics 2021-07-26 Eduardo Ochs

We introduce a new notion of recursively generated enriched term which generalizes the one studied in joint work with Rosick\'y. These new terms come together with a notion of term-interpretability, which recovers the same type of…

Category Theory · Mathematics 2025-07-15 Giacomo Tendas

This paper is part of a series of papers about homotopy theory of strict $n$-categories. In the first paper of this series, we gave conditions that guarantee the existence of a Thomason model category structure on the category of strict…

Algebraic Topology · Mathematics 2015-03-11 Dimitri Ara , Georges Maltsiniotis