Structure and regularity of the singular set in the obstacle problem for the fractional Laplacian

We study the singular part of the free boundary in the obstacle problem for the fractional Laplacian, $\min \left\{(-\Delta)^s u, u-\varphi\right\}=0$ in $\mathbb{R}^n$, for general obstacles $\varphi$. Our main result establishes the complete structure and regularity of the singular set. To prove i...

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Detalles Bibliográficos
Autores: Garofalo, Nicola, Ros, Xavier
Tipo de recurso: artículo
Estado:Versión aceptada para publicación
Fecha de publicación:2019
País:España
Institución:Universidad de Barcelona
Repositorio:Dipòsit Digital de la UB
OAI Identifier:oai:diposit.ub.edu:2445/194048
Acceso en línea:https://hdl.handle.net/2445/194048
Access Level:acceso abierto
Palabra clave:Operadors diferencials parcials
Teoria d'operadors
Equacions en derivades parcials
Processos estocàstics
Partial differential operators
Operator theory
Partial differential equations
Stochastic processes
Descripción
Sumario:We study the singular part of the free boundary in the obstacle problem for the fractional Laplacian, $\min \left\{(-\Delta)^s u, u-\varphi\right\}=0$ in $\mathbb{R}^n$, for general obstacles $\varphi$. Our main result establishes the complete structure and regularity of the singular set. To prove it, we construct new monotonicity formulas of Monneau-type that extend those in those of Garofalo-Petrosyan to all $s \in(0,1)$.