English
Related papers

Related papers: Direct epiperimetric inequalities for the thin obs…

200 papers

We prove new, sharp, wavenumber-explicit bounds on the norms of the Helmholtz single- and double-layer boundary-integral operators as mappings from $L^2(\partial \Omega)\rightarrow H^1(\partial \Omega)$ (where $\partial\Omega$ is the…

Analysis of PDEs · Mathematics 2018-07-26 Jeffrey Galkowski , Euan A. Spence

This article deals with the variable coefficient thin obstacle problem in $n+1$ dimensions. We address the regular free boundary regularity, the behavior of the solution close to the free boundary and the optimal regularity of the solution…

Analysis of PDEs · Mathematics 2016-03-23 Herbert Koch , Angkana Rüland , Wenhui Shi

We consider the Helmholtz transmission problem with one penetrable star-shaped Lipschitz obstacle. Under a natural assumption about the ratio of the wavenumbers, we prove bounds on the solution in terms of the data, with these bounds…

Analysis of PDEs · Mathematics 2022-08-29 Andrea Moiola , Euan A. Spence

We consider the time-harmonic Maxwell equations posed in $\mathbb{R}^3$. We prove a priori bounds on the solution for $L^\infty$ coefficients $\epsilon$ and $\mu$ satisfying certain monotonicity properties, with these bounds valid for…

Analysis of PDEs · Mathematics 2023-10-27 Théophile Chaumont-Frelet , Andrea Moiola , Euan A. Spence

In this note, we use an epiperimetric inequality approach to study the regularity of the free boundary for the parabolic Signorini problem. We show that if the "vanishing order" of a solution at a free boundary point is close to $3/2$ or an…

Analysis of PDEs · Mathematics 2019-11-15 Wenhui Shi

We are concerned with the two-dimensional steady supersonic reacting Euler flow past Lipschitz bending walls that are small perturbations of a convex one, and establish the existence of global entropy solutions when the total variation of…

Analysis of PDEs · Mathematics 2016-11-15 Gui-Qiang Chen , Jie Kuang , Yongqian Zhang

We consider various versions of the obstacle and thin-obstacle problems, we interpret them as variational inequalities, with non-smooth constraint, and prove that they satisfy a new constrained Lojasiewicz inequality. The difficulty lies in…

Analysis of PDEs · Mathematics 2018-09-18 Maria Colombo , Luca Spolaor , Bozhidar Velichkov

We give three different proofs of the log-epiperimetric inequality at singular points for the obstacle problem. In the first, direct proof, we write the competitor explicitly; the second proof is also constructive, but this time the…

Analysis of PDEs · Mathematics 2020-07-07 Luca Spolaor , Bozhidar Velichkov

We obtain new estimates for the solution of both the porous medium and the fast diffusion equations by studying the evolution of suitable Lipschitz norms. Our results include instantaneous regularization for all positive times, long-time…

Analysis of PDEs · Mathematics 2023-09-26 Noemi David , Filippo Santambrogio

We introduce a symmetric (log-)epiperimetric inequality, generalizing the standard epiperimetric inequality, and we show that it implies a growth-decay for the associated energy: as the radius increases energy decays while negative and…

Analysis of PDEs · Mathematics 2023-04-24 Nick Edelen , Luca Spolaor , Bozhidar Velichkov

We study inverse boundary problems for semilinear Schr\"odinger equations on smooth compact Riemannian manifolds of dimensions $\ge 2$ with smooth boundary, at a large fixed frequency. We show that certain classes of cubic nonlinearities…

Analysis of PDEs · Mathematics 2024-02-21 Katya Krupchyk , Shiqi Ma , Suman Kumar Sahoo , Mikko Salo , Simon St-Amant

Non-reversible lifts reduce the relaxation time of reversible diffusions at most by a square root. For reversible diffusions on domains in Euclidean space, or, more generally, on a Riemannian manifold with boundary, non-reversible lifts are…

Probability · Mathematics 2024-12-24 Andreas Eberle , Francis Lörler

Using a direct approach, we prove a $2$-dimensional epiperimetric inequality for the one-phase problem in the scalar and vectorial cases and for the double-phase problem. From this we deduce, in dimension $2$, the $C^{1,\alpha}$ regularity…

Analysis of PDEs · Mathematics 2017-02-10 Luca Spolaor , Bozhidar Velichkov

In this work we study the asymptotic behavior of solutions of the incompressible two-dimensional Euler equations in the exterior of a single smooth obstacle when the obstacle becomes very thin tending to a curve. We extend results by…

Analysis of PDEs · Mathematics 2015-05-13 Christophe Lacave

An inverse problem of finding an obstacle and the boundary condition on its surface from the fixed-energy scattering data is studied. A new method is developed for a proof of the uniqueness results. The method does not use the discreteness…

Mathematical Physics · Physics 2007-05-23 A. G. Ramm

Advantage is taken of the arbitrariness in energy reference to consider anew integral transcriptions of Schrodinger's equation in the presence of potentials which at infinity acquire constant, nonvanishing values. It is found possible to…

Classical Analysis and ODEs · Mathematics 2020-06-08 Jan A. Grzesik

We obtain sharp convergence rates, using Dirichlet correctors, for solutions of wave equations in a bounded domain with rapidly oscillating periodic coefficients. The results are used to prove the exact boundary controllability that is…

Analysis of PDEs · Mathematics 2022-05-17 Fanghua Lin , Zhongwei Shen

Let $\mathcal{M}$ be a smooth submanifold of $\mathbb{R}^n$ equipped with the Euclidean (chordal) metric. This note considers the smallest dimension $m$ for which there exists a bi-Lipschitz function $f: \mathcal{M} \mapsto \mathbb{R}^m$…

Numerical Analysis · Mathematics 2021-05-31 Mark Iwen , Arman Tavakoli , Benjamin Schmidt

We prove the sharp isoperimetric inequality $$ \mathbb{E} \,h_{A}^{\log_{2}(3/2)} \geq \mu(A)^{*} (\log_{2}(1/\mu(A)^{*}))^{\log_{2}(3/2)} $$ for all sets $A \subseteq \{0,1\}^n$, where $\mu$ denotes the uniform probability measure,…

Classical Analysis and ODEs · Mathematics 2023-03-15 David Beltran , Paata Ivanisvili , José Madrid

Let $\Omega \subset \mathbb{R}^n$ be a bounded domain satisfying a Hayman-type asymmetry condition, and let $ D $ be an arbitrary bounded domain referred to as "obstacle". We are interested in the behaviour of the first Dirichlet eigenvalue…

Analysis of PDEs · Mathematics 2017-06-08 Bogdan Georgiev , Mayukh Mukherjee