Improvement of flatness for nonlocal free boundary problems

In this article, we study for the first time the regularity of the free boundary in the one-phase free boundary problem driven by a general nonlocal operator. Our main results establish that the free boundary is C-1,C-alpha near regular points, and that the set of regular free boundary points is ope...

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Detalles Bibliográficos
Autores: Ros-Oton, Xavier, Weidner, M.
Tipo de recurso: artículo
Fecha de publicación:2025
País:España
Institución:Varias* (Consorci de Biblioteques Universitáries de Catalunya, Centre de Serveis Científics i Acadèmics de Catalunya)
Repositorio:Recercat. Dipósit de la Recerca de Catalunya
OAI Identifier:oai:recercat.cat:2072/489131
Acceso en línea:http://hdl.handle.net/2072/489131
Access Level:acceso abierto
Palabra clave:nonlocal
regularity
one-phase problem
free boundary
flatness
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Descripción
Sumario:In this article, we study for the first time the regularity of the free boundary in the one-phase free boundary problem driven by a general nonlocal operator. Our main results establish that the free boundary is C-1,C-alpha near regular points, and that the set of regular free boundary points is open and dense. Moreover, in 2D we classify all blow-up limits and prove that the free boundary is C-1,C-alpha everywhere. The main technical tool of our proof is an improvement of flatness scheme, which we establish in the general framework of viscosity solutions, and which is of independent interest. All of these results were only known for the fractional Laplacian, and are completely new for general nonlocal operators. In contrast to previous works on the fractional Laplacian, our method of proof is purely nonlocal in nature.