On Character Variety of Anosov Representations
Krishnendu Gongopadhyay, Tathagata Nayak
TL;DR
This work analyzes character varieties of Anosov representations of surface groups into ${ m SL}(n,oldsymbol{ olinebreak f C})$. It proves that the moduli spaces of irreducible $(Q^+,Q^-)$-Anosov and of Zariski-dense $(P^+,P^-)$-Anosov representations are complex manifolds with dimension $(2g+k-2)(n^2-1)$ for a $k$-punctured genus $g$ surface, and, in the closed-surface case, carry a natural holomorphic symplectic form. The approach combines Guichard–Wienhard Anosov theory with representation-variety geometry à la Sikora, showing open-ness and smoothness of the Anosov loci and establishing explicit dimension counts. For Γ = π1(Σ_g), the results yield holomorphic symplectic structures on the corresponding Anosov character varieties, providing a higher Teichmüller-type framework within complex geometry.
Abstract
Let $Γ$ be the fundamental group of a $k$-punctured, $k \geq 0$, closed connected orientable surface of genus $g \geq 2$. We show that the character variety of the $(Q^+, Q^-)$-Anosov irreducible representations, resp. the character variety of the $(P^+, P^-)$-Anosov Zariski dense representations of $Γ$ into $\SL(n , \C)$, $n \geq 2$, is a complex manifold of complex dimension \hbox{$(2g+k-2)(n^2-1)$}. For $Γ=π_1(Σ_g)$, we also show that these character varieties are holomorphic symplectic manifolds.
