On Geometric Structures in the Einstein Universe for $\mathrm{SO}_0(p,p+1)$-Hitchin Representations
Colin Davalo, Parker Evans
TL;DR
This work extends the understanding of fiber topology for domains of discontinuity associated with Hitchin representations to the family (SO_0(p,p+1), Ein^{p-1,p}) for p ≥ 3. By combining Higgs-bundle/Data with a pencil-based base analysis and a deformation strategy, the authors show that the quotient M_p → S has fibers that are Ein^{p-1,p-2} when p is odd and T^1 RP^{p-1} when p is even (with exceptional cases p ∈ {4,8} where the tangent bundle is trivial and fibers coincide with Ein^{p-1,p-2}). They implement a robust framework based on Ein-regular pencils, the base-bundle E → RP^{p-1}, and a Nearest-Point Projection technique (via Dav25) to compute the fiber topology, and provide corollaries for G_2'-Hitchin representations. The results deliver new explicit fiber-topology descriptions, enriching the geometric understanding of (G,X)-structures arising from Hitchin components and their G_2-inclusions in higher rank settings.
Abstract
Let $S$ be a closed surface of genus $g \geq 2$. We determine the topology of the fibers of the domain of discontinuity in $\mathrm{Ein}^{p-1,p}$ defined by Guichard-Wienhard and Kapovich-Leeb-Porti for $\mathrm{SO}_0(p,p+1)$-Hitchin representations for $p \geq 3$.
