Uniqueness results in the inverse scattering problem for periodic structures

This paper is concerned with the inverse electromagnetic scattering by a 2D (impenetrable or penetrable) smooth periodic curve. Precisely, we establish global uniqueness results on the inverse problem of determining the grating profile from the scattered fields corresponding to a countably infinite number of quasiperiodic incident waves. For the case of an impenetrable and partially coated perfectly reflecting grating, we prove that the grating profile and its physical property can be uniquely determined from the scattered field measured above the periodic structure. For the case of a penetrable grating, we show that the periodic interface can be uniquely recovered by the scattered field measured only above the interface. A key ingredient in our proofs is a novel mixed reciprocity relation that is derived in this paper for the periodic structures and seems to be new. Copyright © 2012 John Wiley & Sons, Ltd.     

The Minkowski problem for polytopes

The traditional solution to the Minkowski problem for polytopes involves two steps. First, the existence of a polytope satisfying given boundary data is demonstrated. In the second step, the uniqueness of that polytope (up to translation) is then shown to follow from the equality conditions of Minkowski's inequality, a generalized isoperimetric inequality for mixed volumes that is typically proved in a separate context. In this article we adapt the classical argument to prove both the existence theorem of Minkowski and his mixed volume inequality simultaneously, thereby providing a new proof of Minkowski's inequality that demonstrates the equiprimordial relationship between these two fundamental theorems of convex geometry.     

The logarithmic Minkowski problem for polytopes

The logarithmic Minkowski problem asks for necessary and sufficient conditions for a finite Borel measure on the unit sphere so that it is the cone-volume measure of a convex body. This problem was solved recently by Böröczky, Lutwak, Yang and Zhang for even measures (Böröczky et al. (2013) [8]). This paper solves the case of discrete measures whose supports are in general position.     

Uniqueness of solutions for the extended Fisher-Kolmogorov equation

We consider stationary solutions of the Extended Fisher-Kolmogorov (EFK) equation, a fourth-order model equation for bi-stable systems. We show that as long as the stable equilibrium points are real saddles, the paths in the (u, u')-plane of two bounded solutions do not cross. As a consequence we derive that the bounded solutions of the EFK equation correspond exactly to those of the classical Fisher-Kolmogorov equation.     

A flow approach to the planar Lp$L_p$ Minkowski problem

This paper will establish the asymptotic behavior of an anisotropic area-preserving flow which shows the existence of smooth solutions of the planar $L_p$ Minkowski problem for $p\ne 0$.     

Uniqueness results for monopolar fluids

1 FormulationLet fi be a bounded set of R", n 2 2, tv'ith a sufficiently smooth boundary off. ac'e considerthe motion of an incompressible, viscous fluid in fi, which is described by the following systemll]with the initial conditionand the Dirichlet boundary conditionwhere v = (yi, .". u.) is the velocity, p is the pressure, the tensor r = (n j) is defined asp is a. positive constant. Notice that when p = 2 the s}l'steln (1), (2), (5) turns to the N*avierStokes system.A scalar potential to t…     

Uniqueness of a solution to the Cauchy problem for parabolic systems

The Cauchy problem for a second-order Petrovskii parabolic system with bounded and continuous coefficients that are Dini-continuous with respect to space variables is proved to have a unique classical solution in the Tikhonov class.     

The even Orlicz Minkowski problem

The classical Minkowski problem leads to the Lp Minkowski problem and now to the Orlicz Minkowski problem. Existence is demonstrated for the even Orlicz Minkowski problem. A byproduct is a new approach to the solution of the classical Minkowski problem.     

Uniqueness results for nonlocal Hamilton-Jacobi equations

We are interested in nonlocal eikonal equations describing the evolution of interfaces moving with a nonlocal, non-monotone velocity. For these equations, only the existence of global-in-time weak solutions is available in some particular cases. In this paper, we propose a new approach for proving uniqueness of the solution when the front is expanding. This approach simplifies and extends existing results for dislocation dynamics. It also provides the first uniqueness result for a Fitzhugh-Nagumo system. The key ingredients are some new perimeter estimates for the evolving fronts as well as some uniform interior cone property for these fronts.     

Uniqueness of the solution to an inverse thermoelasticity problem

The inverse problem of coupled thermoelasticity is considered in the static, quasi-static, and dynamic cases. The goal is to recover the thermal stress state inside a body from the displacements and temperature given on a portion of its boundary. The inverse thermoelasticity problem finds applications in structural stability analysis in operational modes, when measurements can generally be conducted only on a surface portion. For a simply connected body consisting of a mechanically and thermally isotropic linear elastic material, uniqueness theorems are proved in all the cases under study.     

A remark on rotationally symmetric solutions to the centroaffine Minkowski problem

In this paper we study the solvability of the rotationally symmetric centroaffine Minkowski problem. By delicate blow-up analyses, we remove a technical condition in the existence result obtained by Lu and Wang [30].     

Nonexistence of maximizers for the functional of the centroaffine Minkowski problem

The centroaffine Minkowski problem is studied, which is the critical case of the L _p -Minkowski problem. It admits a variational structure that plays an important role in studying the existence of solutions. In this paper, we find that there is generally no maximizer of the corresponding functional for the centroaffine Minkowski problem.     

Uniqueness in the Cauchy problem for the Koiter shell

We present the uniqueness in the Cauchy problem for the Koiter shell where the model is described by the Riemannian geometry. The Carleman estimates are established by the Bochner technique which yields the uniqueness for the Koiter shell.     

Uniqueness results for the one-dimensional p-Laplacian

This paper is concerned with positive solutions of the boundary value problem ^′(|y^′|^p−2y^′)+f(y)=0, y(−b)=0=y(b) where p>1, b is a positive parameter. Assume that f is continuous on (0,+∞), changes sign from nonpositive to positive, and f(y)/yp−1 is nondecreasing in the interval of f>0. The uniqueness results are proved using a time-mapping analysis.     

The planar Lp dual Minkowski problem

Science China Mathematics - In this paper we study the Lpq-dual Minkowski problem for the case p < 0 < q. We prove for any positive smooth function f on $$mathbb{S}^{1}$$ , there...