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Related papers: Interacting free boundaries in obstacle problems

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In this paper non-transversal intersection of the free and fixed boundary is shown to hold in any dimension for obstacle problems generated by fully nonlinear uniformly elliptic operators. Moreover, $C^1$ regularity results of the free…

Analysis of PDEs · Mathematics 2021-12-14 Emanuel Indrei

In this paper we study regularity properties of the free boundary problem from superconductivity close to a fixed boundary. If the origin is a free boundary point, then we show that the free boundary touches the fixed boundary tangentially.

Analysis of PDEs · Mathematics 2007-05-23 Norayr Matevosyan

We study the regularity of free boundaries in the multiple elastic membrane problem in the plane. We prove the uniqueness of blow-ups, and that the free boundaries are $C^{1,\log}$-curves near a regular intersection point.

Analysis of PDEs · Mathematics 2021-09-22 Ovidiu Savin , Hui Yu

In this investigation we revisit the concept of "effective free surfaces" arising in the solution of the time-averaged fluid dynamics equations in the presence of free boundaries. This work is motivated by applications of the optimization…

Fluid Dynamics · Physics 2012-09-04 R. Yapalparvi , B. Protas

We study the free boundary regularity of the traveling wave solutions to a degenerate advection-diffusion problem of Porous Medium type, whose existence was proved in \cite{MonsaingonNovikovRoquejoffre}. We set up a finite difference scheme…

Analysis of PDEs · Mathematics 2018-11-02 Léonard Monsaingeon

The non-transversal intersection of the free boundary with the fixed boundary is obtained for nonlinear uniformly elliptic operators when $\Omega = \{\nabla u \neq 0\} \cap \{x_n>0\}$ thereby solving a problem in elliptic theory that in the…

Analysis of PDEs · Mathematics 2023-05-05 Emanuel Indrei

One-dimensional free boundary problem for a nonlinear diffusion - convection equation with a Dirichlet condition at fixed face $x=0$, variable in time, is considered. Throught several transformations the problem is reduced to a free…

Analysis of PDEs · Mathematics 2020-02-19 Adriana C. Briozzo , Domingo A. Tarzia

We consider a one-dimensional free boundary problem governed by a nonlinear diffusion - convection equation with a Neumann condition at fixed face $x=0$, which is variable in time and a like Stefan convective condition on the free boundary.…

Analysis of PDEs · Mathematics 2024-10-07 Adriana C. Briozzo

We consider the behaviour of holomorphic functions on a bounded open subset of the plane, satisfying a Lipschitz condition with exponent $\alpha$, with $0<\alpha<1$, in the vicinity of an exceptional boundary point where all such functions…

Complex Variables · Mathematics 2015-09-29 Anthony G. O'Farrell

We extend basic regularity of the free boundary of the obstacle problem to some classes of heterogeneous quasilinear elliptic operators with variable growth that includes, in particular, the $p(x)$-Laplacian. Under the assumption of…

Analysis of PDEs · Mathematics 2014-01-28 S. Challal , A. Lyaghfouri , J. F. Rodrigues , R. Teymurazyan

We consider an elliptic-parabolic free boundary problem that models the fluid flow through a partially saturated porous medium. The free boundary arises as the interface separating the saturated and unsaturated regions. Our main goal is to…

Analysis of PDEs · Mathematics 2025-08-20 Dennis Kriventsov , María Soria-Carro

Building upon the recent results in \cite{FoSp17} we provide a thorough description of the free boundary for the fractional obstacle problem in $\mathbb{R}^{n+1}$ with obstacle function $\varphi$ (suitably smooth and decaying fast at…

Analysis of PDEs · Mathematics 2019-09-20 Matteo Focardi , Emanuele Spadaro

We derive various novel free boundary problems as limits of a coupled bulk-surface reaction-diffusion system modelling ligand-receptor dynamics on evolving domains. These limiting free boundary problems may be formulated as Stefan-type…

Analysis of PDEs · Mathematics 2024-07-24 Amal Alphonse , Diogo Caetano , Charles M. Elliott , Chandrasekhar Venkataraman

We study a class of semilinear free boundary problems in which admissible functions $u$ have a topological constraint, or spanning condition, on their 1-level set. This constraint forces $\{u=1\}$, which is the free boundary, to behave like…

Analysis of PDEs · Mathematics 2026-04-07 Michael Novack , Daniel Restrepo , Anna Skorobogatova

In this paper, we consider the properties of a special free boundary point in the following obstacle problem: The Laplacian of u equals f(x) multiplied by the characteristic function of the set where u is positive within the two-dimensional…

Analysis of PDEs · Mathematics 2026-02-12 Yong Liu

We study a question arising in inverse scattering theory: given a penetrable obstacle, does there exist an incident wave that does not scatter? We show that every penetrable obstacle with real-analytic boundary admits such an incident wave.…

Analysis of PDEs · Mathematics 2021-06-30 Mikko Salo , Henrik Shahgholian

We prove the -- to the best knowledge of the authors -- first result on the fine asymptotic behavior of the regular part of the free boundary of the obstacle problem close to singularities. The result is motivated by our recent partial…

Analysis of PDEs · Mathematics 2023-10-18 Simon Eberle , Henrik Shahgholian , Georg Sebastian Weiss

We report on recent progress in the study of evolution processes involving degenerate parabolic equations what may exhibit free boundaries. The equations we have selected follow to recent trends in diffusion theory: considering anomalous…

Analysis of PDEs · Mathematics 2016-02-17 Jose Antonio Carrillo , Juan Luis Vazquez

We study the parabolic obstacle problem $$\lap u-u_t=f\chi_{\{u>0\}}, \quad u\geq 0,\quad f\in L^p \quad \mbox{with}\quad f(0)=1$$ and obtain two monotonicity formulae, one that applies for general free boundary points and one for singular…

Analysis of PDEs · Mathematics 2013-06-03 Erik Lindgren , Régis Monneau

In this article we investigate the higher regularity properties of the regular free boundary in the fractional thin obstacle problem. Relying on a Hodograph-Legendre transform, we show that for smooth or analytic obstacles the regular free…

Analysis of PDEs · Mathematics 2016-05-24 Herbert Koch , Angkana Rüland , Wenhui Shi