A gradient estimate for nonlocal minimal graphs

We consider the class of measurable functions defined in all of Rn that give rise to a nonlocal minimal graph over a ball of Rn. We establish that the gradient of any such function is bounded in the interior of the ball by a power of its oscillation. This estimate, together with previously known res...

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Detalles Bibliográficos
Autores: Cabré Vilagut, Xavier|||0000-0001-5682-3135, Cozzi, Matteo|||0000-0001-6105-692X
Tipo de recurso: artículo
Fecha de publicación:2019
País:España
Institución:Universitat Politècnica de Catalunya (UPC)
Repositorio:UPCommons. Portal del coneixement obert de la UPC
Idioma:inglés
OAI Identifier:oai:upcommons.upc.edu:2117/134057
Acceso en línea:https://hdl.handle.net/2117/134057
https://dx.doi.org/10.1215/00127094-2018-0052
Access Level:acceso abierto
Palabra clave:Differential equations, Partial
nonlocal minimal surfaces
nonlocal minimal graphs
gradient estimates
regularity results
rigidity theorems
fractional Sobolev inequalities
weak Harnack inequalities.
Equacions diferencials parcials
Àrees temàtiques de la UPC::Matemàtiques i estadística
Descripción
Sumario:We consider the class of measurable functions defined in all of Rn that give rise to a nonlocal minimal graph over a ball of Rn. We establish that the gradient of any such function is bounded in the interior of the ball by a power of its oscillation. This estimate, together with previously known results, leads to the C8 regularity of the function in the ball. While the smoothness of nonlocal minimal graphs was known for n=1,2—but without a quantitative bound—in higher dimensions only their continuity had been established. To prove the gradient bound, we show that the normal to a nonlocal minimal graph is a supersolution of a truncated fractional Jacobi operator, for which we prove a weak Harnack inequality. To this end, we establish a new universal fractional Sobolev inequality on nonlocal minimal surfaces. Our estimate provides an extension to the fractional setting of the celebrated gradient bounds of Finn and of Bombieri, De Giorgi, and Miranda for solutions of the classical mean curvature equation.