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Related papers: Rational approximation for Hitchin representations

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Let $k$ be a finite field and let $G$ be a reductive group over $k[[\pi]]$. Suppose $\mathrm{char}(k)$ is larger than twice the Coxeter number of $G$, we prove the standard endoscopic fundamental lemma for the spherical Hecke algebra of $G$…

Algebraic Geometry · Mathematics 2025-06-10 X. Griffin Wang

The Hitchin component is a connected component of the character variety of reductive group homomorphisms from the fundamental group of a closed surface S of genus greater than 1 to the Lie group PSL_m(R). The Teichmuller space of S…

Geometric Topology · Mathematics 2019-10-31 Giuseppe Martone

Using the Morse-theoretic techniques introduced by Hitchin, we prove that the moduli space of $\Sp(2p,2q)$-Higgs bundles over a compact Riemann surface of genus $g\geq 2$ is connected. In particular, this implies that the moduli space of…

Algebraic Geometry · Mathematics 2017-10-03 Oscar García-Prada , André Oliveira

In this paper we study higher Deligne--Lusztig representations of reductive groups over finite quotients of discrete valuation rings. At even levels, we show that these geometrically constructed representations coincide with certain induced…

Representation Theory · Mathematics 2016-04-07 Zhe Chen , Alexander Stasinski

Ratner's theorem implies topological rigidity of immersed totally geodesic subspaces of noncompact type in finite-volume locally symmetric spaces. In higher rank and infinite volume, however, counter-examples to this rigidity have remained…

Geometric Topology · Mathematics 2026-02-18 Subhadip Dey , Hee Oh

Let $G$ be a discrete group with property (T). It is a standard fact that, in a unitary representation of $G$ on a Hilbert space $\mathcal{H}$, almost invariant vectors are close to invariant vectors, in a quantitative way. We begin by…

Group Theory · Mathematics 2017-11-15 Michal Doucha , Maciej Malicki , Alain Valette

Let $X$ be a compact Riemann surface of genus $g$ and let $x \in X$. We derive the classical presentation of $\pi_1(X,x)$ (i.e the one given by $2g$ generators $a_1,b_1, \dots, a_g,b_g$ and the relation $\prod_{i=1}^g[a_i,b_i] = 1$) from…

Algebraic Topology · Mathematics 2025-02-28 Meirav Amram , Michael Chitayat , Yaacov Kopeliovich

We study the character variety of representations of the fundamental group of a closed surface of genus $g\geq2$ into the Lie group SO(n,n+1) using Higgs bundles. For each integer $0<d\leq n(2g-2),$ we show there is a smooth connected…

Differential Geometry · Mathematics 2017-10-04 Brian Collier

Let G be a real or complex linear algebraic reductive group. Let H and F be reductive subgroups. We study the natural H action on G/F. The main theorem of this note shows that generic H orbits are closed. This theorem is then applied to…

Algebraic Geometry · Mathematics 2008-06-09 M. Jablonski

In this paper, we study the geometric and dynamical properties of maximal representations of surface groups into Hermitian Lie groups of rank 2. Combining tools from Higgs bundle theory, the theory of Anosov representations, and…

Differential Geometry · Mathematics 2019-12-19 Brian Collier , Nicolas Tholozan , Jérémy Toulisse

We prove that level $5$ Witten-Reshetikhin-Turaev $\mathrm{SO}(3)$ quantum representations, also known as the Fibonacci representations, of mapping class groups are locally rigid. More generally, for any prime level $\ell$, we prove that…

Geometric Topology · Mathematics 2025-07-09 Pierre Godfard

For $S$ a closed surface of genus at least $2$, let $\mathrm{Hit}_3(S)$ be the Hitchin component of representations to $\mathrm{SL}(3,\mathbb{R}),$ equipped with the Labourie-Loftin complex structure. We construct a mapping class group…

Differential Geometry · Mathematics 2025-06-12 Christian El Emam , Nathaniel Sagman

We show that for an odd prime r > 3 and an integer g > 1, in the projective representation given by the SO(3) Witten-Chern-Simons theory at an rth root of unity, the image of the mapping class group of a surface of genus g is dense.

Geometric Topology · Mathematics 2009-11-10 Michael Larsen , Zhenghan Wang

We show the set of faithful representations of a closed orientable hyperbolic surface group is dense in both irreducible components of the PSL(2,K) representation variety, where K is the field of real or complex numbers, answering a…

Geometric Topology · Mathematics 2007-05-23 Jason DeBlois , Richard P. Kent

We give necessary and sufficient conditions for a linear reflection group in the sense of Vinberg to be Zariski-dense in the ambient projective general linear group. As an application, we show that every irreducible right-angled Coxeter…

Geometric Topology · Mathematics 2025-04-03 Jacques Audibert , Sami Douba , Gye-Seon Lee , Ludovic Marquis

Given a number field $K$, we show that certain $K$-integral representations of closed surface groups can be deformed to being Zariski dense while preserving many useful properties of the original representation. This generalizes a method…

Geometric Topology · Mathematics 2022-11-17 Michael Zshornack

The main result of this article is that Hitchin representations over real closed field extensions $\mathbb{F}$ of $\mathbb{R}$ correspond precisely to those representations of the fundamental group of a closed surface into…

Geometric Topology · Mathematics 2025-04-01 Xenia Flamm

In the Labourie-Loftin parametrization of the Hitchin component of surface group representations into SL(3,R), we prove an asymptotic formula for holonomy along rays in terms of local invariants of the holomorphic differential defining that…

Differential Geometry · Mathematics 2026-05-21 John Loftin , Andrea Tamburelli , Michael Wolf

We obtain a computational realization of the strong approximation theorem. That is, we develop algorithms to compute all congruence quotients modulo rational primes of a finitely generated Zariski dense group $H \leq \mathrm{SL}(n,…

Group Theory · Mathematics 2019-05-08 Alla Detinko , Dane Flannery , Alexander Hulpke

We give an exact formula for the dimension of the variety of homomorphisms from $S_g$ to $\mathit{any}$ semisimple real algebraic group, where $S_g$ is a surface group of genus $g \geq 2$.

Representation Theory · Mathematics 2017-04-19 Krishna Kishore