ON MAXWELL EQUATIONS WITH THE TRANSPARENT BOUNDARY CONDITION

In this paper we show the well-posedness and stability of the Maxwell scattering problem with the transparent boundary condition. The proof depends on the well-posedness of the time-harmonic Maxwell scattering problem with complex wave numbers which is also established.     

Boundary stabilization of vibration of nonlocal micropolar elastic media

In this paper, we study the stabilization problem of vibration of linearized three-dimensional nonlocal micropolar elasticity. For this purpose, we need to demonstrate the well-posedness of the system of equations governing the vibration of three-dimensional nonlocal micropolar media for both forced (i.e. with boundary feedback) and unforced cases. We assume the non-homogeneous system of equations for the unforced (uncontrolled) case to establish the well-posedness. It should be pointed out that the well-posedness of the evolution equations in micropolar case has been studied by many authors; but, the well-posedness in the nonlocal micropolar is an open problem. Our tools in well-posedness analysis are the semigroup techniques. Afterwards, we pursue the stabilization problem and show that the vibration of the nonlocal micropolar elastic media will be eventually dissipated under boundary feedback actions consisting of stress and couple stress feedback laws. These control laws are simple, linear and can be easily implemented in practical applications. The stabilization proof is accomplished using Lyapunov stability and LaSalle’s invariant set theorems.     

Asymptotic behavior of solutions of a free boundary problem modeling multi-layer tumor growth in presence of inhibitor

In this paper we study well-posedness and asymptotic behavior of solution of a free boundary problem modeling the growth of multi-layer tumors under the action of an external inhibitor. We first prove that this problem is locally well-posed in little Hölder spaces. Next we investigate asymptotic behavior of the solution. By computing the spectrum of the linearized problem and using the linearized stability theorem, we give the rigorous analysis of stability and instability of all stationary flat solutions under the non-flat perturbations. The method used in proving these results is first to reduce the free boundary problem to a differential equation in a Banach space, and next use the abstract well-posedness and geometric theory for parabolic differential equations in Banach spaces to make the analysis.     

Initial–boundary value problems for conservation laws with source terms and the Degasperis–Procesi equation

We consider conservation laws with source terms in a bounded domain with Dirichlet boundary conditions. We first prove the existence of a strong trace at the boundary in order to provide a simple formulation of the entropy boundary condition. Equipped with this formulation, we go on to establish the well-posedness of entropy solutions to the initial–boundary value problem. The proof utilizes the kinetic formulation and the averaging lemma. Finally, we make use of these results to demonstrate the well-posedness in a class of discontinuous solutions to the initial–boundary value problem for the Degasperis–Procesi shallow water equation, which is a third order nonlinear dispersive equation that can be rewritten in the form of a nonlinear conservation law with a nonlocal source term.     

A free boundary problem of diffusion equation with integral condition

We consider a free boundary problem of heat equation with integral condition on the unknown free boundary. Results of solution regularity and problem well-posedness are presented.     

Well-posedness of Korteweg-de Vries-Burgers equation on a finite domain

In this paper,we consider the Korteweg-de Vries-Burgers equation on a finite domain with initial value and nonhomogeneous boundary conditions. This particular problem arises in the theory of ferroelectricity. We first get the local well-posedness of the problem, and then under the help of the local result, we use nonlinear interpolation to have the global well-posedness of the problem.     

An algorithm for solving a linear two-point boundary value problem for an integrodifferential equation

family of algorithms for solving a linear two-point boundary value problem is constructed in terms of the data of the integrodifferential equation and the boundary condition involved. The convergence conditions for the algorithms are established, and necessary and sufficient conditions for the well-posedness of the problem are found.     

Kreiss symmetrizer and boundary conditions for the Euler-Korteweg system in a half space

The Euler-Korteweg system is a third order, dispersive system of PDEs, obtained from the standard Euler equations for compressible fluids by adding the so-called Korteweg stress tensor - encoding capillarity effects. Various results of well-posedness have been obtained recently for the Cauchy problem associated with the Euler-Korteweg system in the whole space. As to mixed problems, with initial and boundary value data, they are still mostly open. Here the linearized Euler-Korteweg system is studied in a half space by the use of normal mode analysis, which yields a generalized Kreiss-Lopatinski? condition that must be satisfied by the boundary conditions for the boundary value problem to be well-posed.Conversely, under the uniform Kreiss-Lopatinski? condition, generalized Kreiss symmetrizers are constructed in one space dimension for an extended system originally introduced for the Cauchy problem, which displays crucial quasi-homogeneity properties. A priori estimates without loss of derivatives are thus derived, and finally the well-posedness of the mixed problem is obtained by combining the estimates for the pure boundary value problem and trace results for solutions of the pure Cauchy problem.     

一类退化椭圆型方程边值问题的适定性

研究一类特殊退化椭圆型方程边值问题的适定性,该类问题与双曲空间中的极小图的Dirichlet问题,曲面的无穷小等距形变刚性问题等等的研究密切相关,而这类方程的特征形式在区域上是变号的,其适定性是值得深入讨论的.最后,得到这类边值问题的H~1弱解的存在性和唯一性.     

Well-Posed and Regular Nonlocal Boundary-Value Problems for Partial Differential Equations

The present paper deals with the well-posedness and regularity of one class of one-dimensional time-dependent boundary-value problems with global boundary conditions on the entire time interval. We establish conditions for the well-posedness of boundary-value problems for partial differential equations in the class of bounded differentiable functions. A criterion for the regularity of the problem under consideration is also obtained.     

Global Exact Boundary Controllability for Cubic Semi-linear Wave Equations and Klein-Gordon Equations

The authors prove the global exact boundary controllability for the cubic semi-linear wave equation in three space dimensions, subject to Dirichlet, Neumann, or any other kind of boundary controls which result in the well-posedness of the corresponding initial-boundary value problem. The exponential decay of energy is first established for the cubic semi-linear wave equation with some boundary condition by the multiplier method, which reduces the global exact boundary controllability problem to a local one. The proof is carried out in line with [2, 15]. Then a constructive method that has been developed in [13] is used to study the local problem. Especially when the region is star-complemented, it is obtained that the control function only need to be applied on a relatively open subset of the boundary. For the cubic Klein-Gordon equation, similar results of the global exact boundary controllability are proved by such an idea.     

Kinetic boundary layers: on the adequate discretization of the Boltzmann collision operator

We develop criteria for the discretization of the Boltzmann collision operator under which linearized kinetic boundary layers exhibit the same algebraic structure as their continuous counterparts. These criteria are shown to be sufficient for the well-posedness of kinetic boundary layers. After the analysis of the discrete layer, an example illustrates how to include models which lead to differential algebraic problems. Existence and uniqueness of nonlinear boundary layers adjacent to an equilibrium state are proven.     

Well-posedness of hyperbolic initial boundary value problems

Assuming that a hyperbolic initial boundary value problem satisfies an a priori energy estimate with a loss of one tangential derivative, we show a well-posedness result in the sense of Hadamard. The coefficients are assumed to have only finite smoothness in view of applications to nonlinear problems. This shows that the weak Lopatinskii condition is roughly sufficient to ensure well-posedness in appropriate functional spaces.     

An initial boundary value problem for one-dimensional shallow water magnetohydrodynamics in the solar tachocline

In this article we investigate the shallow water magnetohydrodynamic equations in space dimension one with Dirichlet boundary conditions only for the velocity. This model has been proposed to study the phenomena in the solar tachocline. In this article, the local well-posedness in time of the model is proven by constructing the approximate solutions and showing the strong convergence of the approximate solutions.     

On a Class of Coupled Variational Formulations for a Nonlinear Parabolic Equation

51.Introducti0nSince198O)stheoriesandapplicationsofboundaryelementmethods(BEM)orboundaryintegralmethods(BIM)havemadegreatsuccessesfortheparaboliclnit1alboundaryvalueproblems(seeL1-12j),andtheapproachhasbeenappliedtonumericalsolutionsofinitialboundaryva1ueproblemssuccessfully(seeL1-5j'L8j).Thepropertiesofboundaryelementoperatorshavebeenstudiedbyboundaryintegralmethodsbymanyauthors(see.[4j,L6J'[7j'L12J).Theseresultsprovideabasisforconvergencesanderrorestimatesfornumericalapproximationofbou…     

Initial value problems for creeping flow of Maxwell fluids

We consider the flow of nonlinear Maxwell fluids in the unsteady quasistatic case, where the effect of inertia is neglected. We study the well-posedness of the resulting PDE initial-boundary value problem locally in time. This well-posedness depends on the unique solvability of an elliptic boundary value problem. We first present results for the 3D case with sufficiently small initial data and for a simple shear flow problem with arbitrary initial data; after that we extend our results to some 3D flow problems with large initial data.We solve our problem using an iteration between linear subproblems. The limit of the iteration provides the solution of our original problem.     

A Problem with Nonlocal Conditions for Partial Differential Equations Unsolved with Respect to the Leading Derivative

In the domain that is the product of a segment and a p-dimensional torus, we investigate the well-posedness of a problem with nonlocal boundary conditions for a partial differential equation unsolved with respect to the leading derivative with respect to a selected variable. We establish conditions for the the classical well-posedness of the problem and prove metric theorems on the lower bounds of small denominators appearing in the course of its solution.     

A Class of Evolutionary Problems with an Application to Acoustic Waves with Impedance Type Boundary Conditions.

A well-posedness result for a time-shift invariant class of evolutionary operator equations is considered and exemplified by an application to an impedance type initial boundary value problem for the system of linear acoustics. The problem class allows for memory effects in the domain as well as on the domain boundary. (© 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)     

Boundary value problem for a first-order linear parabolic system

A boundary value problem for a linear parabolic system is considered. Sufficient conditions for the well-posedness of the problem are found. The spline collocation method on a uniform grid is used to construct a high-order accurate implicit difference scheme, and its absolute stability is proved.