Epstein surfaces for $G-$opers
Joaquín Lema
TL;DR
The paper develops a higher-rank generalization of Epstein surfaces for $G$-opers, constructing Epstein surfaces Ep$(z)$ inside the symmetric space $bX$ via osculation with a fixed Fuchsian oper. It provides a concrete, normalized parametrization of the oper moduli via the Hitchin base, and establishes quantitative regularity and curvature bounds for Ep, enabling a criteria for $oldsymbol{ riangle}$-Anosov holonomy through Davalo’s nearly geodesic framework. The results yield explicit neighborhoods of Anosov opers around the Fuchsian locus, applicable to general $G$ and sharpened in cyclic cases, with consequences for domains of discontinuity and transversality. The work links developing maps, osculation maps, and the asymptotic geometry of holonomies, contributing to the understanding of Anosov representations in higher rank and their geometric structures.”
Abstract
Given a complex semisimple Lie group $G$, we introduce the notion of an Epstein surface associated to a $G$-oper. These surfaces generalize Epstein's classical construction for $G=PGL_2 (\mathbb{C})$. As an application, we provide a criterion that ensures that the holonomy of the oper is $Δ-$Anosov. Finally, we discuss how the developing map of the oper interacts with domains of discontinuity of the holonomy (whenever Anosov) and the transversality properties it satisfies. Along the way, we provide a quick review of opers that we hope serves as a self-contained introduction.
