Rank $n$ swapping algebra for the $\operatorname{PSL}(n, \mathbb{R})$ Hitchin component

TL;DR

This paper introduces the rank n swapping algebra, a new algebraic structure with Poisson properties, to characterize the Hitchin component for PSL(n, R), extending Labourie's work and connecting to cluster spaces.

Contribution

The paper defines the rank n swapping algebra, proves its well-definedness, and uses it to characterize PSL(n, R) Hitchin components, extending Labourie's framework.

Findings

Defined the rank n swapping algebra and established its properties.

Introduced a cross-ratio in the algebra's fraction field.

Characterized the Hitchin component using cross-ratios within the algebra.

Abstract

F. Labourie [arXiv:1212.5015] characterized the Hitchin components for $\operatorname{PSL}(n, \mathbb{R})$ for any $n>1$ by using the swapping algebra, where the swapping algebra should be understood as a ring equipped with a Poisson bracket. We introduce the rank $n$ swapping algebra, which is the quotient of the swapping algebra by the $(n+1)\times(n+1)$ determinant relations. The main results are the well-definedness of the rank $n$ swapping algebra and the "cross-ratio" in its fraction algebra. As a consequence, we use the sub fraction algebra of the rank $n$ swapping algebra generated by these "cross-ratios" to characterize the $\operatorname{PSL}(n, \mathbb{R})$ Hitchin component for a fixed $n>1$. We also show the relation between the rank $2$ swapping algebra and the cluster $\mathcal{X}_{\operatorname{PGL}(2,\mathbb{R}),D_k}$-space.