设$f \in L_{loc}^1 (\R^n)\cap \mathcal{S}$,其中$\mathcal{S}$是Schwartz分布类,和$$\int_{σ(D)} f(x) dx = 0 \quad \forall σ\in G, \qquad (*)$$,其中$D\subset \R^n$是一个有界区域,其闭包$\bar{D}$是一个闭球,$S$是它的边界。则comp $ is connected and path connected. By $ G $ the group of all rigid motions of $ \R^n $ is denoted. This group consists of all translations and rotations. A proof of the following theorem is given. Theorem 1. {\it Assume that $ n=2 $, $ f \not \equiv 0 $, and (*) holds. Then $ D $ is a ball.} Corollary. {\it If the problem $(\nabla^2 +k^2)u=0 $ in $ D $, $ u_N|_S=0 $, $ u|_S=const \neq 0 $ has a solution, th…
A bounded domain $Ω$ in a Riemannian manifold $M$ is said to have the Pompeiu property if the only continuous function which integrates to zero on $Ω$ and on all its congruent images is the zero function. In some respects, the Pompeiu property can be viewed as an overdetermined problem, given its relation with the Schiffer problem. It is well-known that every Euclidean ball fails the Pompeiu property while spherical balls have the property for almost all radii (Ungar's Freak theorem). In the present paper we discuss the Pompeiu property when $M$ is compact and admits an isoparametric foliation…
We consider positive singular solutions of PDEs arising from double phase functionals. Exploiting a rather new version of the moving plane method originally developed by Sciunzi, we prove symmetry and monotonicity properties of such solutions.
We deal with Monge-Ampère type equations modeled upon general anisotropic norms $H$ in $\mathbb R^n$. An overdetermined problem for convex solutions to these equations is analyzed. The relevant solutions are subject to both a homogeneous Dirichlet condition and a second boundary condition, designed on $H$, on the gradient image of the domain. The Wulff shape symmetry associated with $H$ of the solutions is established.
The main thrust of our current work is to exploit very specific characteristics of a given problem in order to acquire improved compactness for supercritical problems and to prove existence of new types of solutions. To this end, we shall develop a variational machinery in order to construct a new type of classical solutions for a large class of supercritical elliptic partial differential equations.\\ The issue of symmetry and symmetry breaking is challenging and fundamental in mathematics and physics. Symmetry breaking is the source of many interesting phenomena namely phase transitions, inst…
We continue the study of positive singular solutions of PDEs arising from double phase functionals started in [6]. In particular, we consider the case $p<q < 2$, and we relax the assumption on the capacity of the singular set using an intrinsic notion of capacity.
One-dimensional symmetry for the solutions of a three-dimensional water wave problem
我们证明了一个一维对称性结果的加权狄利克雷到诺依曼问题所产生的模型中的水波在3维。更精确地说,我们证明了极小和有界单调解决方案只依赖于一个欧几里德变量。在De La Llave和第三作者的一篇文章中建立了二维情况下(并且没有权重)的类似结果。在本文中,一个关键的成分,在证明中给出了通过比较参数获得的极小的能量估计。
We study symmetry and quantitative approximate symmetry for an overdetermined problem involving the fractional torsion problem in a bounded domain $Ω\subset \mathbb R^n$. More precisely, we prove that if the fractional torsion function has a $C^1$ level surface which is parallel to the boundary $\partial Ω$ then the domain is a ball. If instead we assume that the solution is close to a constant on a parallel surface to the boundary, then we quantitatively prove that $Ω$ is close to a ball. Our results use techniques which are peculiar to the nonlocal case as, for instance, quantitative version…
In this work, we employ the technique developed in arXiv:2109.11255 to prove rotational symmetry for a class of Serrin-type problems for the standard laplacian. We also discuss in some length how our strategy compares with the classical moving plane method.
We obtain the radial symmetry of the solution to a partially overdetermined boundary value problem in a convex cone in space forms by using the maximum principle for a suitable subharmonic function $P$ and integral identities. In dimension $2$, we prove Serrin-type results for partially overdetermined problems outside a convex cone. Furthermore, we obtain a Rellich identity for an eigenvalue problem with mixed boundary conditions in a cone.
We consider the problem of shock reflection on a solid wall in plane symmetry for a barotropic fluid. We establish a local in time solution after the point of reflection, thereby determining the state behind the reflected shock. The location of the reflected shock in space time being unknown the problem constitutes a free boundary problem. Furthermore, the quantity describing the thermodynamic state of the fluid along the wall being also unknown, complete data for the problem is only given in a single point, the reflection point.