一类退化椭圆方程组正解的存在性和唯一性

In this paper we study a class of degenerate nonlinear elliptic systems with homogeneous Dirichlet boundary conditions by the monotone iteration method. The existence and uniqueness of the positive solution of such a system are proved. In particular conditions which ensure that the iteration process converges to the unique solution are given.     

Boundary Feedback Stabilization of Naghdi＇s Model

We consider the stabilization of Naghdi‘s model by boundary feedbacks where the model has a middle surface of any shape. First, applying the semigroup approach and the regularity of elliptic boundary value problems, we obtain the existence, the uniqueness, and the properties of solutions to Naghdi‘s model. Finally, we establish the exponential decay rates for Naghdi‘s model under some checkable geometric conditions on the middle surface.     

The quasi-reversibility method to solve the Cauchy problems for parabolic equations

In this paper, on the one hand, we take the conventional quasi-reversibility method to obtain the error estimates of approximate solutions of the Cauchy problems for parabolic equations in a sub-domain of QT with strong restrictions to the measured boundary data. On the other hand, weakening the conditions on the measured data, then combining the duality method in optimization with the quasi-reversibility method, we solve the Cauchy problems for parabolic equations in the presence of noisy data. Using this method, we can get the proper regularization parameter ε that we need in the quasi-reversibility method and obtain the convergence rate of approximate solutions as the noise of amplitude δ tends to zero.     

OSCILLATION THEOREM TO SYSTEMS OF IMPULSIVE NEUTRAL DELAY PARABOLIC PARTIAL DIFFERENTIAL EQUATIONS

In this paper,we study the oscillation of solutions to the systems of impul- sive neutral delay parabolic partial differential equations.Under two different boundary conditions,we obtain some sufficient conditions for oscillation of all solutions to the systems.     

EXISTENCE AND NONEXISTENCE OF ENTIRE LARGE SOLUTIONS FOR SOME SEMILINEAR ELLIPTIC EQUATIONS

In this note, we consider positive entire large solutions for semilinear elliptic equations Au = p（x）f（u） in R^N with N ≥ 3. More precisely, we are interested in the link between the existence of entire large solution with the behavior of solution for --△u = p（x） in R^N. Especially for the radial case, we try to give a survey of all possible situations under Keller-Osserman type conditions.     

BLOW-UP OF SOLUTIONS TO ELLIPTIC EQUATIONS WITH SEMILINEAR DYNAMICAL BOUNDARY CONDITIONS OF HYPERBOLIC TYPE

In this paper,we present some sufficient conditions for blow-up of soluti- ons to elliptic equations under semilinear dynamical boundary conditions of hyperbolic type.     

Regularity criteria for the three-dimensional MHD equations

In this paper,we consider regularity criteria for solutions to the 3D MHD equations with incompressible conditions.By using some classical inequalities,we obtain the regularity of strong solutions to the three-dimensional MHD equations under certain sufficient conditions in terms of one component of the velocity field and the magnetic field respectively.     

Managing procurement and production outsourcing under dynamic prices

This paper proposes a procurement and production outsourcing model subject to a dynamic prices environment. Using the optimal control theory we obtain the necessary conditions of the optimal procurement and production policy. From the study of optimal control conditions, we derive qualitative properties of the optimal procurement and production decisions for a few exemplifying cases. Through these results we are able to provide some managerial implications for managers to make real decisions.     

TRIPLE SYMMETRIC POSITIVE SOLUTIONS TO NONLINEAR BVP WITH INTEGRAL BOUNDARY VALUE CONDITIONS

In the paper,we consider a nonlinear boundary value problem with integral boundary value conditions.By a generalization of the Leggett-Williams fixed-point theorem,we provide sufficient conditions for the existence of at least three positive solutions to the problem.An example is introduced to demonstrate our result.     

ASYMPTOTIC BEHAVIOR OF SOLUTIONS TO A CLASS OF HIGHER ORDER DIFFERENCE EQUATIONS

In this paper,we study the asymptotic behavior of solutions to a class of higher order difference equations.With the aid of the discrete inequality,we obtain some sufficient conditions which ensure that all the solutions to the equation are some high order of infinities,and also that some conditions which guarantee that every oscillatory solution to the equation has the property that the i order L operator of it tends to infinity when its independent variable tends to zero.     

Almost Sure Convergence of the General Jamison Weighted Sum of $$ {\user1{B}} $$-Valued Random Variables

In this paper．two new functions are introduced to depict the Jamison weighted sum of random variables instead using the common methods．their properties and relationships are systematically discussed．We also analysed the implication of the conditions in previous papers．Then we apply these consequences to B-valued random variables．and greatly improve the original results of the strong convergence of the general Janfison weighted sum．Furthermore,our discussions are useful to the corresponding questions of real-valued random variables．     

Conditions of topological conjugacy of gradient-like diffeomorphisms on irreducible 3-manifolds

In this paper, we obtain the topological classification of gradient-like diffeomorphisms and the conditions of topological conjugacy of Morse-Smale diffeomorphisms with finite sets of heteroclinic trajectories on three-dimensional manifolds.Translated fromMatematicheskie Zametki, Vol. 59, No. 1, pp. 73–80, January, 1996.This research was partially supported by the Russian Foundation for Basic Research under grant No. 93-01-01-407, by the International Science Foundation under grant R99000, and by the Foundation Cultural Initiative.     

Multiple solutions for a semilinear equation involving singular potential and critical exponent

Variational methods are used to prove the existence of positive and sign-changing solutions for a semilinear equation involving singular potential and critical exponent in any bounded domain.*supported in part by Tian Yuan Foundation of NNSF (A0324612)**Supported by 973 Chinese NSF and Foundation of Chinese Academy of Sciences.***Supported in part by NNSF of China.Received: September 23, 2002; revised: November 30, 2003     

The existence of a weak solution of inhomogeneous quasilinear elliptic equation with critical growth conditions

In this paper, we get the existence of a weak solution of the following inhomogeneous quasilinear elliptic equation with critical growth conditions: Supported by the Youth Foundation, Natural Science Foundation, People's Republic of China.     

On twistor Gauss maps of surfaces in 4-spheres

In this paper we study surfaces in S⁴ and their twistor Gauss maps. Some necessary and sufficient conditions that the twistor Gauss map is harmonic are given. We find many examples of nonisotropic harmonic maps from a surface to P ³.Supported by the National Natural Science Foundation of China and the Science Foundation of Zhejiang Province.     

Nonlinear Degenerate Parabolic Equation with Nonlinear Boundary Condition

In this paper, we obtain the necessary and sufficient conditions on the global existence of all positive （weak） solutions to a nonlinear degenerate parabolic equation with nonlinear boundary condition.     

A linear quadratic optimal control problem with disturbances—An algebraic Riccati equation and differential games approach

A linear quadratic optimal control problem with coexisting initial and persistent disturbances is studied. Upper and lower values and relevant algebraic Riccati equations (ARE for short) are introduced. Various relations among these values are presented. The solvability of the resulting AREs is shown to be closely related to the solvability of the original optimal control problem. A formula is obtained for the solution of one of the AREs, which is of nonstandard form. Several unexpected features of the original problem are revealed from the standpoint of differential games. Some known results on the so-calledH optimal control problem are recovered.This work was partially supported by the Chinese NSF under Grant 19131050, the Chinese State Education Commission Science Foundation, the SEDC Foundation for Young Academics, and the Fok Ying Tung Education Foundation.     

Adaptive Algorithms of Nonlinear Approximation with Finite Terms

This paper deals with realizable adaptive algorithms of the nonlinear approximation with finite terms based on wavelets. We present a concrete algorithm by which we may find the required index set Am for the greedy algorithm Gm^P（., Ψ）. This makes the greedy algorithm realize the near best approximation in practice. Moreover, we study the efficiency of the finite-term approximation of another Mgorithm introduced by Birge and Massart.     

Wavelets and Wavelet Packets Related to a Class of Dilation Matrices

The construction of wavelets generated from an orthogonal multiresolution analysis can be reduced to the unitary extension of a matrix, which is not easy in most cases. Jia and Micchelli gave a solution to the problem in the case where the dilation matrix is 21 and the dimension does not exceed 3. In this paper, by the method of unitary extension of a matrix, we obtain the construction of wavelets and wavelet oackets related to a class of dilation matrices.     

Rigidity of holomorphic curves in complex Grassmann manifolds

In this paper it is proved that the holomorphic curves in complex Grassmann manifolds are uniquely determined by its first and second fundamental forms, up to rigid motion.Supported by the National Natural Science Foundation of China and the President Foundation of Graduate School of the Chinese Academy of Sciences.