English
Related papers

Related papers: Representation homology of simply connected spaces

200 papers

Let $G$ be a reductive affine algebraic group defined over a field $k$ of characteristic zero. In this paper, we study the cotangent complex of the derived $G$-representation scheme $ {\rm DRep}_G(X)$ of a pointed connected topological…

Algebraic Topology · Mathematics 2019-02-13 Yuri Berest , Ajay C. Ramadoss , Wai-kit Yeung

Let G be a connected reductive complex affine algebraic group, and let X denote the moduli space of G-valued representations of a rank r free group. We first characterize the singularities in X, extending a theorem of Richardson and proving…

Algebraic Geometry · Mathematics 2022-02-25 Clément Guérin , Sean Lawton , Daniel Ramras

We prove new structural results for the rational homotopy type of the classifying space $B\operatorname{aut}(X)$ of fibrations with fiber a simply connected finite CW-complex $X$. We first study nilpotent covers of $B\operatorname{aut}(X)$…

Algebraic Topology · Mathematics 2025-10-15 Alexander Berglund , Tomáš Zeman

In this paper, we introduce and study representation homology of topological spaces, which is a natural homological extension of representation varieties of fundamental groups. We give an elementary construction of representation homology…

Algebraic Topology · Mathematics 2020-02-25 Yuri Berest , Ajay C. Ramadoss , Wai-kit Yeung

Building on Quillen's rational homotopy theory, we obtain algebraic models for the rational homotopy theory of parametrised spectra. For any simply-connected space $X$ there is a dg Lie algebra $\Lambda_X$ and a (coassociative…

Algebraic Topology · Mathematics 2021-05-05 Vincent Braunack-Mayer

Let G be a connected, complex reductive Lie group with maximal compact subgroup K, and let X denote the moduli space of G- or K-valued representations of a rank r free group. In this article, we develop methods for studying the…

Algebraic Topology · Mathematics 2018-05-09 Carlos Florentino , Sean Lawton , Daniel Ramras

Let $p \colon Y \to X$ be a finite, regular cover of finite graphs with associated deck group $G$, and consider the first homology $H_1(Y;\mathbb{C})$ of the cover as a $G$-representation. The main contribution of this article is to broaden…

Geometric Topology · Mathematics 2023-12-05 Xenia Flamm

A global representation is a compatible collection of representations of the outer automorphism groups of the groups belonging to some collection of finite groups $\mathscr{U}$. Global representations assemble into an abelian category…

Representation Theory · Mathematics 2026-05-20 Miguel Barrero , Tobias Barthel , Luca Pol , Neil Strickland , Jordan Williamson

We study the derived representation scheme DRep_n(A) parametrizing the n-dimensional representations of an associative algebra A over a field of characteristic zero. We show that the homology of DRep_n(A) is isomorphic to the…

Representation Theory · Mathematics 2015-03-13 Yuri Berest , Giovanni Felder , Sasha Patotski , Ajay C. Ramadoss , Thomas Willwacher

For a semisimple complex algebraic group $G$ we determine the rational cohomology and the Hodge-Tate structure of the moduli stack ${\mathscr B}un_{G,X}$ of principal $G$-bundles over a connected smooth complex projective variety $X$ of…

Algebraic Geometry · Mathematics 2025-08-06 Pedro L. del Angel R. , Frank Neumann

We study the cup product on the Hochschild cohomology of the stack quotient [X/G] of a smooth quasi-projective variety X by a finite group G. More specifically, we construct a G-equivariant sheaf of graded algebras on X whose G-invariant…

Algebraic Geometry · Mathematics 2018-12-13 Cris Negron , Travis Schedler , Pieter Belmans , Pavel Etingof

It is well known that the moduli space of flat connections on a trivial principal bundle MxG, where G is a connected Lie group, is isomorphic to the representation variety Hom(\pi_1(M), G)/G. For a tiling T, viewed as a marked copy of R^d,…

General Topology · Mathematics 2010-02-09 H. O. Erdin

We survey some of the known results on the relation between the homology of the {\em full} Hecke algebra of a reductive $p$-adic group $G$, and the representation theory of $G$. Let us denote by $\CIc(G)$ the full Hecke algebra of $G$ and…

K-Theory and Homology · Mathematics 2007-05-23 Victor Nistor

We prove the strong Macdonald conjecture of Hanlon and Feigin for reductive groups G. In a geometric reformulation, we show that the Dolbeault cohomology $H^q(X;\Omega^p)$ of the loop Grassmannian X is freely generated by de Rham's forms on…

Algebraic Geometry · Mathematics 2016-09-07 Susanna Fishel , Ian Grojnowski , Constantin Teleman

We describe various equivalent ways of associating to an orbifold, or more generally a higher \'etale differentiable stack, a weak homotopy type. Some of these ways extend to arbitrary higher stacks on the site of smooth manifolds, and we…

Algebraic Topology · Mathematics 2016-10-18 David Carchedi

Let G be a finite group acting tamely on a proper reduced curve C over an algebraically closed field. We study the G-module structure on the cohomology groups of a G-equivariant locally free sheaf F on C, and give formulas of…

Algebraic Geometry · Mathematics 2026-01-12 Qing Liu , Wenfei Liu

Let $X$ be a smooth projective curve of genus $g \geq 3$, and let $G$ be a nontrivial connected reductive affine algebraic group over $\mathbb{C}$. Examining the moduli spaces of regularly stable $G$-Higgs bundles and holomorphic…

Algebraic Geometry · Mathematics 2026-03-03 Sumit Roy

Given a finitely-generated group $\pi$ and a linear algebraic group $G$, the representation variety Hom$(\pi,G)$ has a natural filtration by the characteristic varieties associated to a rational representation of $G$. Its algebraic…

Algebraic Topology · Mathematics 2016-11-17 Daniela Anca Macinic , Stefan Papadima , Clement Radu Popescu , Alexander I. Suciu

Let X be a homogeneous space of a connected linear algebraic group G' over a number field k, containing a k-point x. Assume that the stabilizer of x in G' is connected. Using the notion of a quasi-trivial group, recently introduced by…

Number Theory · Mathematics 2008-05-10 Mikhail Borovoi

We consider a series of four subexceptional representations coming from the third line of the Freudenthal-Tits magic square; using Bourbaki notation, these are fundamental representations $(G',X)$ corresponding to $(C_3, \omega_3),\, (A_5,…

Algebraic Geometry · Mathematics 2021-06-24 András C. Lőrincz , Jerzy Weyman
‹ Prev 1 2 3 10 Next ›