Rigidity of Totally Geodesic Hypersurfaces in Negative Curvature

Author:

Ben Lowe

Keyword:

Mathematics, Differential Geometry, Differential Geometry (math.DG), Dynamical Systems (math.DS)

journal:

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date:

2023-06-01 16:00:00

Abstract

Let $M$ be a closed hyperbolic manifold containing a totally geodesic hypersurface $S$, and let $N$ be a closed Riemannian manifold homotopy equivalent to $M$ with sectional curvature bounded above by $-1$. Then it follows from the work of Besson-Courtois-Gallot that $\pi_1(S)$ can be represented by a hypersurface $S'$ in $N$ with volume less than or equal to that of $S$. We study the equality case: if $\pi_1(S)$ cannot be represented by a hypersurface $S'$ in $N$ with volume strictly smaller than that of $S$, then must $N$ be isometric to $M$? We show that many such $S$ are rigid in the sense that the answer to this question is positive. On the other hand, we construct examples of $S$ for which the answer is negative.