Spherical volume and spherical Plateau problem
Antoine Song
TL;DR
This work introduces the spherical Plateau problem as an infinite‑dimensional variational model for a topological invariant called the spherical volume, defined via integral currents on the spherical quotient $S^\infty/\lambda_\Gamma(\Gamma)$. Central technical tools include Ambrosio–Kirchheim metric currents, Wenger’s intrinsic flat compactness, and a barycenter map with a sharp Jacobian bound that underpins intrinsic uniqueness results. The authors prove intrinsic uniqueness of spherical Plateau solutions for closed hyperbolic manifolds (and extend the paradigm to 3‑manifolds), establishing an intrinsic rigidity that ties the spherical Plateau solution to canonical geometric structures scaled by $\frac{(n-1)^2}{4n}g_0$ or $\frac13 g_{\mathrm{hyp}}$ in dimension 3. They also develop an analogue of Dehn fillings via Plateau‑level constructions, showing asymptotic rigidity: as the filling tori injectivity radii blow up, the spherical Plateau solutions converge to the underlying hyperbolic core, thereby providing a higher‑dimensional counterpart to Thurston’s Dehn filling phenomenon. Together, these results connect a variational, current‑theoretic framework with classical rigidity, entropy, and geometric decomposition phenomena, and open several questions about well‑ordering and extrinsic rigidity in broader settings.
Abstract
Given a closed oriented manifold or more generally a group homology class, we introduce the spherical Plateau problem, which is a variational problem corresponding to a topological invariant called the spherical volume. In principle, its solutions should be realized by minimal surfaces in quotients of spheres. We explain that in many geometrically interesting cases, those solutions are essentially unique. We start with a review of the Ambrosio-Kirchheim theory of metric currents, and the barycenter map method developed by Besson-Courtois-Gallot. Then, we outline the following applications: (1) the intrinsic uniqueness of spherical Plateau solutions for negatively curved, locally symmetric, closed oriented manifolds, (2) the intrinsic uniqueness of spherical Plateau solutions for all 3-dimensional closed oriented manifolds, (3) the construction of higher-dimensional analogues of hyperbolic Dehn fillings. We also propose some open questions.
