An extension problem related to the fractional Laplacian

L Caffarelli, L Silvestre - Communications in partial differential …, 2007 - Taylor & Francis
The operator square root of the Laplacian (−▵) 1/2 can be obtained from the harmonic
extension problem to the upper half space as the operator that maps the Dirichlet boundary …

Regularity estimates for the solution and the free boundary of the obstacle problem for the fractional Laplacian

LA Caffarelli, S Salsa, L Silvestre - Inventiones mathematicae, 2008 - Springer
We use a characterization of the fractional Laplacian as a Dirichlet to Neumann operator for
an appropriate differential equation to study its obstacle problem. We write an equivalent …

Obstacle problems and free boundaries: an overview

X Ros-Oton - SeMA Journal, 2018 - Springer
Free boundary problems are those described by PDEs that exhibit a priori unknown (free)
interfaces or boundaries. These problems appear in physics, probability, biology, finance, or …

Nonlinear porous medium flow with fractional potential pressure

LA Caffarelli, JL Vazquez - arXiv preprint arXiv:1001.0410, 2010 - arxiv.org
We study a porous medium equation, with nonlocal diffusion effects given by an inverse
fractional Laplacian operator. We pose the problem in n-dimensional space for all t> 0 with …

Nonlinear diffusion with fractional Laplacian operators

JL Vázquez - Nonlinear partial differential equations: the Abel …, 2012 - Springer
We describe two models of flow in porous media including nonlocal (long-range) diffusion
effects. The first model is based on Darcy's law and the pressure is related to the density by …

[图书][B] Integro-differential elliptic equations

X Fernández-Real, X Ros-Oton - 2024 - Springer
Progress in Mathematics is a series of books intended for professional mathematicians and
scientists, encompassing all areas of pure mathematics. This distinguished series, which …

Generic regularity of free boundaries for the obstacle problem

A Figalli, X Ros-Oton, J Serra - Publications mathématiques de l'IHÉS, 2020 - Springer
The goal of this paper is to establish generic regularity of free boundaries for the obstacle
problem in R n R^n. By classical results of Caffarelli, the free boundary is C∞ C^∞ outside a …

The obstacle problem for nonlinear integro-differential operators

J Korvenpää, T Kuusi, G Palatucci - Calculus of Variations and Partial …, 2016 - Springer
We investigate the obstacle problem for a class of nonlinear equations driven by nonlocal,
possibly degenerate, integro-differential operators, whose model is the fractional p …

On the fine structure of the free boundary for the classical obstacle problem

A Figalli, J Serra - Inventiones mathematicae, 2019 - Springer
In the classical obstacle problem, the free boundary can be decomposed into “regular” and
“singular” points. As shown by Caffarelli in his seminal papers (Caffarelli in Acta Math 139 …

Some new monotonicity formulas and the singular set in the lower dimensional obstacle problem

N Garofalo, A Petrosyan - Inventiones mathematicae, 2009 - Springer
We construct two new one-parameter families of monotonicity formulas to study the free
boundary points in the lower dimensional obstacle problem. The first one is a family of Weiss …