Manifolds with kinks and the asymptotic behavior of the graph Laplacian operator with Gaussian kernel
Susovan Pal, David Tewodrose
TL;DR
This work extends the fundamental link between graph Laplacians and Laplace–Beltrami operators to manifolds with kinks, comprising interiors, boundaries, corners, and cusps. By introducing and exploiting inward tangent sectors and Bouligand cones, the authors derive exact small-bandwidth expansions for intrinsic and extrinsic Gaussian graph operators, showing leading behavior along inward directions and boundary-corrective terms. They establish concentration results under alpha-subexponential tails, providing concrete sample-size–bandwidth tradeoffs for convergence to first-order differential operators with Neumann-like boundary interpretations. The framework unifies interior and singular-point behavior, offers refined error bounds, and is validated through numerical experiments on balls, cubes, and cusps. The results pave the way for principled spectral analysis and Neumann-type boundary conditions for graphs built from data on kinked manifolds.
Abstract
We introduce manifolds with kinks, a class of manifolds with possibly singular boundary that notably contains manifolds with smooth boundary and corners. We derive the asymptotic behavior of the Graph Laplace operator with Gaussian kernel and its deterministic limit on these spaces as bandwidth goes to zero. We show that this asymptotic behavior is determined by the inward sector of the tangent space and, as special cases, we derive its behavior near interior and singular points. Lastly, we show the validity of our theoretical results using numerical simulation.
