A Weierstrass extremal field theory for the fractional Laplacian

In this paper, we extend, for the first time, part of the Weierstrass extremal field theory in the Calculus of Variations to a nonlocal framework. Our model case is the energy functional for the fractional Laplacian (the Gagliardo–Sobolev seminorm), for which such a theory was still unknown. We buil...

Descripción completa

Detalles Bibliográficos
Autores: Cabré Vilagut, Xavier|||0000-0001-5682-3135, Urtiaga Erneta, Iñigo|||0000-0002-7306-2961, Felipe Navarro, Juan Carlos|||0000-0001-7630-6661
Tipo de recurso: artículo
Fecha de publicación:2023
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:2117/404687
Acceso en línea:https://hdl.handle.net/2117/404687
https://dx.doi.org/10.1515/acv-2022-0099
Access Level:acceso abierto
Palabra clave:Weierstrass field theory
Field of extremals
Fractional Laplacian
Calibration
Null-Lagrangian
Minimality
Classificació AMS::53 Differential geometry::53C Global differential geometry
Classificació AMS::35 Partial differential equations::35J Partial differential equations of elliptic type
Classificació AMS::47 Operator theory::47G Integral, integro-differential, and pseudodifferential operators
Àrees temàtiques de la UPC::Matemàtiques i estadística
Descripción
Sumario:In this paper, we extend, for the first time, part of the Weierstrass extremal field theory in the Calculus of Variations to a nonlocal framework. Our model case is the energy functional for the fractional Laplacian (the Gagliardo–Sobolev seminorm), for which such a theory was still unknown. We build a null-Lagrangian and a calibration for nonlinear equations involving the fractional Laplacian in the presence of a field of extremals. Thus, our construction assumes the existence of a family of solutions to the Euler–Lagrange equation whose graphs produce a foliation. Then the minimality of each leaf in the foliation follows from the existence of the calibration. As an application, we show that monotone solutions to fractional semilinear equations are minimizers. In a forthcoming work, we generalize the theory to a wide class of nonlocal elliptic functionals and give an application to the viscosity theory.