English
Related papers

Related papers: A model structure via orbit spaces for equivariant…

200 papers

We introduce type-theoretic algebraic weak factorisation systems and show how they give rise to homotopy-theoretic models of Martin-L\"of type theory. This is done by showing that the comprehension category associated to a type-theoretic…

Category Theory · Mathematics 2022-06-30 Nicola Gambino , Marco Federico Larrea

Let $\bf C$ be a coreflective subcategory of a cofibrantly generated model category $\bf D$. In this paper we show that under suitable conditions $\bf C$ admits a cofibrantly generated model structure which is left Quillen adjunct to the…

Algebraic Topology · Mathematics 2013-04-15 Tadayuki Haraguchi

A weakly equivariant Hopf algebra is a Hopf algebra A with an action of a finite group G up to inner automorphisms. We show that each weakly equivariant Hopf algebra can be replaced by a Morita equivalent algebra B with a strict action of G…

Rings and Algebras · Mathematics 2012-05-07 Jennifer Maier , Thomas Nikolaus , Christoph Schweigert

The purpose of this paper is to develop a homotopical algebra for graphs, relevant to zeta series and spectra of finite graphs. More precisely, we define a Quillen model structure in a category of graphs (directed and possibly infinite,…

Combinatorics · Mathematics 2008-02-27 Terrence Bisson , Aristide Tsemo

We construct a model structure on the category $\mathrm{DblCat}$ of double categories and double functors, whose trivial fibrations are the double functors that are surjective on objects, full on horizontal and vertical morphisms, and fully…

Algebraic Topology · Mathematics 2023-06-21 Lyne Moser , Maru Sarazola , Paula Verdugo

This is the second of a series of papers which are devoted to a comprehensive theory of maps between orbifolds. In this paper, we develop a basic machinery for studying homotopy classes of such maps. It contains two parts: (1) the…

Algebraic Topology · Mathematics 2007-05-23 Weimin Chen

We study $\omega$-equifibrations between weak $\omega$-categories in the sense of Batanin--Leinster. We define $\omega$-equifibrations as a natural weak $\omega$-categorical analogue of isofibrations between categories, and show that they…

Category Theory · Mathematics 2025-11-14 Soichiro Fujii , Keisuke Hoshino , Yuki Maehara

For a complex semi-simple Lie algebra, every nilpotent orbit in its projectivization comes with a complex contact structure. For each nilpotent orbit, we classify projective Legendrian subvarieties that are homogeneous under the actions of…

Complex Variables · Mathematics 2026-03-10 Minseong Kwon

We formulate and prove examples of a conjecture which describes the W-algebras in type A as successive quantum Hamiltonian reductions of affine vertex algebras associated with several hook-type nilpotent orbits. This implies that the affine…

Representation Theory · Mathematics 2025-03-26 Thomas Creutzig , Justine Fasquel , Andrew R. Linshaw , Shigenori Nakatsuka

We extend the theory of equivariant orthogonal spectra from finite groups to profinite groups, and more generally from compact Lie groups to compact Hausdorff groups. The G-homotopy theory is "pieced together" from the G/U-homotopy theories…

Algebraic Topology · Mathematics 2014-11-11 Halvard Fausk

We provide the expected constructions of weakly $\omega$-categorified models (in the sense of Bressie) of the theory of groups and quandles which arise by replacing the homotopies used to give equivalence relations in the theory of…

Category Theory · Mathematics 2020-06-30 Phillip M Bressie , David N Yetter

In previous work, we showed that there are appropriate model category structures on the category of simplicial categories and on the category of Segal precategories, and that they are Quillen equivalent to one another and to Rezk's complete…

Algebraic Topology · Mathematics 2013-01-04 Julia E. Bergner

For a $C^{*}$-category with a strict $G$-action we construct examples of equivariant coarse homology theories. To this end we first introduce versions of Roe categories of objects in $C^{*}$-categories which are controlled over bornological…

K-Theory and Homology · Mathematics 2023-06-21 Ulrich Bunke , Alexander Engel

We prove that a weak equivalence between two cofibrant (colored) props in chain complexes induces a Dwyer-Kan equivalence between the simplicial localizations of the associated categories of algebras. This homotopy invariance under base…

Algebraic Topology · Mathematics 2014-05-05 Sinan Yalin

Let F be the flag variety of a complex semi-simple group G, let H be an algebraic subgroup of G acting on F with finitely many orbits, and let V be an H-orbit closure in F. Expanding the cohomology class of V in the basis of Schubert…

Algebraic Geometry · Mathematics 2007-05-23 Michel Brion

In this paper we present the general theory of cleft extensions for a cocommutative weak Hopf algebra $H$. For a weak left $H$-module algebra we obtain a bijective correspondence between the isomorphisms classes of $H$-cleft extensions…

Quantum Algebra · Mathematics 2012-10-05 N. Alonso Álvarez , J. M. Fernández Vilaboa , R. González Rodríguez

We derive a new sufficient condition for the existence of {\omega}-categorical universal structures in classes of relational structures with constraints, augmenting results by Cherlin, Shelah, Chi, and Hubi\v{c}ka and Ne\v{s}et\v{r}il.…

Logic · Mathematics 2012-03-29 Christian Pech , Maja Pech

Given any model category, or more generally any category with weak equivalences, its simplicial localization is a simplicial category which can rightfully be called the "homotopy theory" of the model category. There is a model category…

Algebraic Topology · Mathematics 2007-05-23 Julia E. Bergner

Associated to each small category $C$, there is a category of $C$-shaped diagrams of simplicial sets and an $\infty$-category of $NC$-shaped homotopy coherent diagrams of spaces. We present a functor which exhibits the latter as the…

Algebraic Topology · Mathematics 2022-08-01 Severin Bunk

Let G be a real reductive algebraic group with maximal compact subgroup K, and let F be a rank r free group. Here, we summarize the construction of a natural strong deformation retraction from the space of closed orbits in Hom(F,G)/G to the…

Algebraic Topology · Mathematics 2016-09-23 Ana Casimiro , Carlos Florentino , Sean Lawton , André Oliveira