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Related papers: Positivity and higher Teichm\"uller theory

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We introduce the notion of $\Theta$-positivity in real simple Lie groups. This notion at the same time generalizes Lusztig's total positivity in split real Lie groups and invariant orders in Lie groups of Hermitian type. We show that there…

Differential Geometry · Mathematics 2024-04-30 Olivier Guichard , Anna Wienhard

These notes transcribe a workshop about the notion of total positivity and $\Theta$-positivity and its relation to Higher Teichm\"uller Theory. $\Theta$-positivity is a notion of positivity in semisimple Lie groups and was recently…

Differential Geometry · Mathematics 2022-12-09 Xenia Flamm , Arnaud Maret

In this article we revisit a new notion of positivity in real semisimple Lie groups that at the same time generalizes total positivity in split real Lie groups as well as positive Lie semigroups in Hermitian Lie groups of tube type. We…

Group Theory · Mathematics 2025-11-18 Anna Wienhard

In arXiv:1802.02833 Guichard and Wienhard introduced the notion of $\Theta$-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…

Differential Geometry · Mathematics 2026-02-11 Olivier Guichard , François Labourie , Anna Wienhard

In this (partly expository) paper we show, using ideas from the theory of total positivity, how a number of properties of a semisimple group over the complex numbers can be presented purely in terms of the Weyl group. We also describe some…

Representation Theory · Mathematics 2025-09-24 G. Lusztig

We prove that $\Theta$-positive representations of fundamental groups of surfaces (possibly cusped or of infinite type) satisfy a collar lemma, and their associated cross-ratios are positive. As a consequence we deduce that…

Differential Geometry · Mathematics 2024-09-11 Jonas Beyrer , Olivier Guichard , François Labourie , Beatrice Pozzetti , Anna Wienhard

We develop the theory of $\Theta$-positive representations from general Fuchsian groups to linear groups over real closed fields. Our definition, which does not assume the boundary map to be continuous, encompasses many generalizations of…

Geometric Topology · Mathematics 2026-05-25 Xenia Flamm , Nicolas Tholozan , Tianqi Wang , Tengren Zhang

The first part of this paper surveys several characterizations of Teichm\"uller space as a subset of the space of representation of the fundamental group of a surface into PSL(2,R). Special emphasis is put on (bounded) cohomological…

Geometric Topology · Mathematics 2011-12-06 Marc Burger , Alessandra Iozzi , Anna Wienhard

The theory of total positivity for reductive groups is here extended to the case of symmetric spaces.

Representation Theory · Mathematics 2021-09-29 G. Lusztig

Let W be a Weyl group. We can define the notion of positivity of a W-module in terms of the corresponding module over the asymptotic Iwahori-Hecke algebra. We state a conjecture which says that certain explicit W-modules are positive and we…

Representation Theory · Mathematics 2026-01-19 G. Lusztig

This paper is a survey on the role of Higgs bundle theory in the study of higher Teichm\"uller spaces. Recall that the Teichm\"uller space of a compact surface can be identified with a certain connected component of the moduli space of…

Algebraic Geometry · Mathematics 2019-01-29 Oscar García-Prada

We construct "quantum theta bases," extending the set of quantum cluster monomials, for various versions of skew-symmetric quantum cluster algebras. These bases consist precisely of the indecomposable universally positive elements of the…

Representation Theory · Mathematics 2021-06-16 Ben Davison , Travis Mandel

Let W be a Weyl group. We introduce the notion of positive conjugacy class in W. This generalizes the notion of regular elliptic conjugacy class in the sense of Springer.

Representation Theory · Mathematics 2020-09-21 G. Lusztig

Refection Positivity is a central theme at the crossroads of Lie group representations, euclidean and abstract harmonic analysis, constructive quantum field theory, and stochastic processes. This book provides the first presentation of the…

Representation Theory · Mathematics 2018-02-27 Karl-Hermann Neeb , Gestur Olafsson

For Grassmannians, Lusztig's notion of total positivity coincides with positivity of the Plucker coordinates. This coincidence underpins the rich interaction between matroid theory, tropical geometry, and the theory of total positivity.…

Combinatorics · Mathematics 2024-10-30 Grant Barkley , Jonathan Boretsky , Christopher Eur , Jiyang Gao

In recent years, Teichm\"uller theory, which is the study of moduli spaces of marked Riemann surfaces, has come to be considered more and more from the point of view of actions of surface groups inside certain semi-simple Lie groups. In…

Differential Geometry · Mathematics 2016-05-17 François Fillastre , Graham Smith

We study the positive theory of groups acting on trees and show that under the presence of weak small cancellation elements, the positive theory of the group is trivial, i.e. coincides with the positive theory of a non-abelian free group.…

Group Theory · Mathematics 2019-10-22 Montserrat Casals-Ruiz , Albert Garreta , Javier de la Nuez González

M. Hochster defines an invariant namely $\Theta(M,N)$ associated to two finitely generated module over a hyper-surface ring $R=P/f$, where $P=k\{x_0,...,x_n\}$ or $k[X_0,...,x_n]$, for $k$ a field and $f$ is a germ of holomorphic function…

Algebraic Geometry · Mathematics 2017-02-10 Mohammad Reza Rahmati

Using Lusztig's total positivity in split real Lie groups V. Fock and A. Goncharov have introduced spaces of positive (framed) representations. For general semisimple Lie groups a generalization of Lusztig's total positivity was recently…

Differential Geometry · Mathematics 2022-10-24 Olivier Guichard , Eugen Rogozinnikov , Anna Wienhard

In this article, using a twisted version of H\"ormander's $L^2$-estimate, we give new characterizations of notions of partial positivity, which are uniform $q$-positivity and RC-positivity. We also discuss the definition of uniform…

Complex Variables · Mathematics 2020-12-17 Takahiro Inayama
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