2026/01/15 by Michael Bleher, Denis Brazke, Sebastian Nill · 1 voice
Mathematics · #math.AP #math.DG
We study a family of non-local isoperimetric energies Eγ,ε on the round sphere M = Sn, where the non-local interaction kernel Kε is the fundamental solution of the Helmholtz operator 1 - ε2 Δ. To analyse these energies, we introduce a Riemannian autocorrelation function cΩ associated to a measurable set Ω⊂ M, defined on any compact, connected, oriented Riemannian manifold without boundary (Mn,g) of dimension n≥2. This function is intimately linked to Matheron's set covariogram from convex geometry. By establishing a characterisation of functions of bounded variation BV(M) in terms of geodesic difference quotients, we show that Ω has finite perimeter if and only if cΩ is Lipschitz, and we relate the Lipschitz constant to the perimeter of Ω. We show that on the round sphere Eγ,ε admits a reformulation in terms of cΩ, which allows us to compute the limit as ε → 0 in a variational sense, that is, in the framework of Γ-convergence.