Positivity and representations of surface groups

Fuente: arXiv
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Main Authors: Guichard, Olivier, Labourie, François, Wienhard, Anna
Format: Preprint
Published: 2021
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author Guichard, Olivier
Labourie, François
Wienhard, Anna
author_facet Guichard, Olivier
Labourie, François
Wienhard, Anna
contents In arXiv:1802.02833 Guichard and Wienhard introduced the notion of $Θ$-positivity, a generalization of Lusztig's total positivity to real Lie groups that are not necessarily split. Based on this notion, we introduce in this paper $Θ$-positive representations of surface groups. We prove that $Θ$-positive representations are $Θ$-Anosov. This implies that $Θ$-positive representations are discrete and faithful and that the set of $Θ$-positive representations is open in the representation variety. We show that the set of $Θ$-positive representations is closed within the set of representations that do not virtually factor through a parabolic subgroup. From this we deduce that for any simple Lie group $\mathsf G$ admitting a $Θ$-positive structure there exist components consisting of $Θ$-positive representations. More precisely we prove that the components parametrized using Higgs bundles methods in arXiv:2101.09377 consist of $Θ$-positive representations.
format Preprint
id arxiv_https___arxiv_org_abs_2106_14584
institution arXiv
publishDate 2021
record_format arxiv
spellingShingle Positivity and representations of surface groups
Guichard, Olivier
Labourie, François
Wienhard, Anna
Differential Geometry
Group Theory
Geometric Topology
11-XX, 14-XX
In arXiv:1802.02833 Guichard and Wienhard introduced the notion of $Θ$-positivity, a generalization of Lusztig's total positivity to real Lie groups that are not necessarily split. Based on this notion, we introduce in this paper $Θ$-positive representations of surface groups. We prove that $Θ$-positive representations are $Θ$-Anosov. This implies that $Θ$-positive representations are discrete and faithful and that the set of $Θ$-positive representations is open in the representation variety. We show that the set of $Θ$-positive representations is closed within the set of representations that do not virtually factor through a parabolic subgroup. From this we deduce that for any simple Lie group $\mathsf G$ admitting a $Θ$-positive structure there exist components consisting of $Θ$-positive representations. More precisely we prove that the components parametrized using Higgs bundles methods in arXiv:2101.09377 consist of $Θ$-positive representations.
title Positivity and representations of surface groups
topic Differential Geometry
Group Theory
Geometric Topology
11-XX, 14-XX
url https://arxiv.org/abs/2106.14584