THE CONNECTIVITY OF Z-TRANSFORMATION GRAPHS OF PERFECT MATCHINGS OF HEXAGONAL SYSTEMS

Let H be a hexagonal system.The Z-transformation graph Z(H) is a graph where the vertices are perfect matchings of H and where two perfect matchings are joined by an edge provided their symmetric difference consists of six edges of a hexagon of H. We prove that the connectivity of Z(H) is equal to the minimum degree of vertices of Z(H).     

OSCILLATION OF SYSTEMS OF IMPULSIVE DELAY PARABOLIC EQUATIONS ABOUT BOUNDARY VALUE PROBLEMS

In this paper,oscillation of solutions to a class of impulsive delay para- bolic partial differential equations system with higher order Laplace operator is studied.Under two different boundary value conditions,we establish some sufficient criteria with respect to the oscillations of such systems,employing first-order impulsive delay differential inequalities.The results fully reflect the influence action of impulsive and delay in oscillation.     

THE APPLICATION OF STABLE GROUPS TO BIOLOGICAL STRUCTURES

The properties of the stable group theory are discussed. The mathematical models of the insect legs, a pair of hands, and human chromosomes are established using stable group theory. The two postulates: the prime-number principle and the symmetric principle, and a new evolution theory in the biology are suggested. The brain structures and the structures of the nervous system can be studied using above two principles.     

THE BOUNDARY VALUE PROBLEMS FOR THE HIGHER ORDER QUASILINEAR PARABOLIC AND ELLIPTIC SYSTEMS SATISFYING GENERAL BOUNDARY CONDITIONS

In this paper, the existence and uniqueness of the boundary value problems for the higher order quasilinear parabolic systems satisfying general boundary conditions and initial value condition are considered. We have concluded the problems to the following: if all the solutions of a family of problems of the same type which are derived from a substitution of τf(s, t, u, ...,Dx~(2b-1)u), τgj(y, t, u) and τ(x) (0≤τ≤1) for f, g, and φ respectively are uniformly bounded, then the original problems have a unique solution in H~(2b a,1 a/2b)((?)_T). Under assumption that the linear problems have a unique solution, we have proved the existence and uniqueness of the solution of the boundary value problems for the quasillnear elliptic systems.     

SOME BOUNDARY PROBLEMS OF THE SPIN SYSTEMS AND THE SYSTEMS OF FERRO-MAGNETIC CHAIN Ⅱ. Mixed Problems and Others

In the present paper the authors considered the mixed problem with nonlinear boundary conditions and the initial condition for the spin system and the system of ferro-magnetic chain in the rectangular domain Q_t.     

ON THE STABILITY OF DIFFERENTIAL SYSTEMS WITH TIME LAG

In this paer the inequality of Lemma 1 of [1] is extended.By means of our inequality and the method of Lyapunov function we study the stability of two kinds of large seate differential systems with time lag and the stability of a higher -order differential equation with time lag.The sufficient conditions for the stability(S.),the asymptotic stability(A.S.),the uniformly asymptotic stability(U.A.S) and the exponential asymptotic stability(E.A.S.) of the zero solutions of the systerms are obtained respectively.     

ON THE SPECTRUM OF SINGULAR HAMILTONIAN DIFFERENTIAL SYSTEMS

In this paper, we study a bounded-below singular Hamiltonian system. Sufficient and necessary conditions are obtained for the existence and the number of eigenvalues on the left-axis. The main results of this paper are the extension and improvement of Weyl spectral theorem for singular second order differential equations.     

DISTORTION ESTIMATES OF SYMMETRIC POINTS OF QUASICIRCLE

Let ξ=f(z) be a K-quasiconformal mapping (K-Q.C.) in the complex plane, f(∞)=∞. The image of the real axis under ξ=f(z) is a quasicirclz and the points ξ=f(z) and ξ=f(z) are a pair of symmetric points of the circle, we know that the connection between the quasicircle and the quasiconformal extention is essential. The distortion estimates of the quasicircle and of the symmetric points are both interesting. It is known that there exist two constants C_1(K) and C_2(K), depending on K oniy, such that the inequality     

THE INTERACTIONS OF SHOCK WAVES OF NONSTRICTLY HYPERBOLIC SYSTEMS

The interaction of shock waves is investigated for the following nonstrictly hyperbolic system:The interaction of shock waves is complicated, with new types of shock waves, and new singula rities in the dependence of interaction on the relative positions of the three states separated by shock waves. Several ideas are introduced to helo organize and clarify the new phenomena.     

THE DECAY BEHAVIOR OF SOLUTIONS FOR NONLOCAL BOUNDARY PROBLEMS

A parabolic equation defined on a bounded domain with boundary condition being nonlocal is considered. The existence and the dynamic behavior of the solutions for linear and semilinear equations are investigated in special spaces. One will find that the behavior of the solutions are affected by the boundary conditions. A semigroup approach is employed in this paper.     

RIEMANN-HILBERT PROBLEMS OF DEGENERATE HYPERBOLIC SYSTEM

This paper is concerned with the Riemann-Hilbert problems of degenerate hyperbolic system in two general domains, where the boundary curves are given by the parameter equations of the arc length s. We prove the existence and uniqueness of solutions to the Riemann-Hilbert problems by conformal deformations. The corre-sponding representations of solutions to the problems are also presented.     

EXPLICIT DISSIPATIVE SCHEMES FOR BOUNDARY PROBLEMS OF GENERALIZED SCHRDINGER SYSTEMS

In this paper, the author constructs a class of explicit schemes, spanning two time levels, forthe initial--boundary-value problems of generalized nonlinear Schrodinger systems, and proves theconvergence of these schemes with a series of prior estimates. For a single Schrodinger equation, theschemes are identical with those of the article [1].     

POSITIVE SOLUTIONS TO A SEMILINEAR SYSTEM OF SECOND-ORDER TWO-POINT BOUNDARY VALUE PROBLEMS

By using Krasnosel'skii fixed point theorem of cone expansion-compression type, the results on the existence of one, two and three positive solutions are established for a semilinear second-order system of two-point boundary value problems.     

ON THE WEAK DISCONTINUITY SURFACES AND TAPES OF EQUATION SYSTEMS IN FLUID MECHANICS

The weak discontinuity surfaces for a system of quasi-linear differential equations of higher order are developed.The classification of equation systems in fluid mechanics is based on the propagative weak discontinuity surfaces.Types of equations for different flow models are discussed.The conclusion is as follows:(a) For incompressible nonviscous flow,incompressible viscous flow and compressible viscous flow,the types of equations are all parabolic in the unsteady case and elliptic in the steady case.(b) For compressible nonviscous flow,the type of equations is hyperbolic in the unsteady case or steady supersonic case,and the type is elliptic in the steady subsonic case.     

MATCHED QUEUEING SYSTEMS WITH A DOUBLE INPUT

In this paper, we study the matched queueing system with a double input, MoM/PH/1,where the two inputs are two independent Poisson processes, and the service time is of PH-distribution.The L.S. transforms and the expectations of the distributions of occupation time and virtual waiting time of the type-Ⅰ customer are derived.The probability that the server is working, the mean non-idle period, and the mean busy period are also derived. The related algorithms are given with numerical results.     

ON PRIMALITY OF THE COMBINATION OF EXPONENTIAL FUNCTIONS

The author discusses in this paper the transcendental unsolvability of the functionalequation F(z)=fog(z) with f being meromorphic and g entire,for the function of theformwhere Q_j's are rational,P_j's are polynomials. The main results are:a) F(z) is pseudo-prime, i. e. F=fog has no transcendental solutions f and g;b)If 0≤n_1相似文献   

ON THE VISCOSITY SPLITT NG METHOD FOR INITIAL BOUNDARY VALUE PROBLEMS OF THE NAVIAR-STOKES EQUATIONS

The viscosily splitting method for the Navier-Stokes equations on two dimensional multi-connected domains is considered. The equation is split into an Euler equation and a non-stationary Stekes equation within each time step. The author proves the convergence theorem as he has done for the problem on simply connected domains, and the rate of convergence is improved from loss than 1/4 to 1.     

PROPERTIES IN THE LARGE OF QUADRATIC SYSTEMS IN THE PLANE

The author proves that any quadratic system in the plane can be changed into the quadratic system (E_1) or (E_2) by means of linear transformations, and then gives a necessary and sufficient condition for the systems (E_1) and (E_2) to be bounded for t≥0 and to have precisely one monotone unboundol orbit for t≥0 respectively.     

QUALITATIVE THEORY OF THE KUKLES SYSTEMS:(Ⅰ) NUMBER OF CRITICAL POINTS

The special cubic system (a natural and simPlest generaIization of thequadratic system of C1ass (l) to cubic system)f.'x = yl y = --x 6y a,x' a2xy a,y' a#x' a,x'y a.xy' a,y' (1)was first studied by the Russian Mathematician I.S.KukIes [ll on the Ilecessaryand sufficient conditions fot O(0,0) to be a ccnter of (1). After [ll, the sameproblem and also the order of O as a fine fOcus were also studied iIl [2--l0] and[13-19], so (l) is now called as a "Kukles system". In l988-…     

EXISTENCE OF SOLUTIONS OF A FAMILY OF NONLINEAR BOUNDARY VALUE PROBLEMS IN L^2-SPACES

By using the perturbation results of sums of ranges of accretive mappings of Calvert and Gupta (1978),the abstract results on the existence of solutions of a family of nonlinear boundary value problems in L^2 (Ω) are studied. The equation discussed in this paper and the methods used here are extension and complement to the corresponding results of Wei Li and He Zhen‘s previous papers. Especially,some new techniques are used in this paper.