A nonlocal approximation of the area in codimension two
Michele Caselli, Mattia Freguglia, Nicola Picenni
TL;DR
The paper introduces a fractional $s$-mass for codimension-two surfaces in $\mathbb{R}^n$ by pairing a linking constraint with a fractional Sobolev energy, and proves that $(1-s)^2\mathbb{M}_s(\Sigma)$ Γ-converges, under flat convergence of boundaries, to the $(n-2)$-dimensional area with multiplicity $\frac{2\pi\omega_{n-1}}{n}\sum_i d_i\mathcal{H}^{n-2}(\Sigma_i)$. The authors establish both a liminf inequality via slicing and a local positivity argument, and a matching limsup construction using vortex-type configurations and a Ginzburg-Landau reduction to obtain energy upper bounds. The results generalize the codimension-one BBM-type convergence to codimension two, with the correct $(1-s)^2$ scaling, and are local in nature, suggesting robust extensions to ambient Riemannian manifolds and to higher codimensions. The framework is poised for min-max applications to existence and regularity questions for codimension-two minimal-like objects, and connects fractional Sobolev energies, linking theory, and geometric measure theory in a unified relaxation approach to area minimization.
Abstract
For $s\in (0,1)$ we introduce a notion of fractional $s$-mass on $(n-2)$-dimensional closed, orientable surfaces in $\R^n$. Moreover, we prove its $Γ$-convergence, with respect to the flat topology, and pointwise convergence to the $(n-2)$-dimensional area.
