Invariant Curves of Reversible Mappings with Small Twist

In this paper,we are concerned with the existence of invariant curves of reversible mappings.A variant of the classical small twist theorem is given.     

半无穷区间上二阶三点边值问题的多个正解的存在性(英文)

In this paper,we are concerned with the existence of multiple positive solutions to a second-order three-point boundary value problem on the half-line.The results are obtained by the Leggett-Williams fixed point theorem.     

Pseudo almost periodic solutions for the systems of differential equations with piecewise constant argument [<Emphasis Type="Italic">t</Emphasis> + 1/2]

In this paper we investigate the existence and uniqueness of pseudo almost periodic solutions and unboundedness of other solutions for the systems of differential equations with piecewise constant argument [t + 1/2] by means of new notion of pseudo almost periodic vector sequences. The case in which the characteristic equation has multiple roots is considered.     

EXISTENCE OF MULTIPLE POSITIVE PERIODIC SOLUTIONS TO A CLASS OF INTEGRO-DIFFERENTIAL EQUATION

In this paper,by the Avery-Henderson fixed point theorem,we investigate the existence of multiple positive periodic solutions to a class of integro-differential equation. Some suficient conditions are obtained for the existence of multiple positive periodic solutions.     

CONSTRUCTING EXAMPLES WITH 5 EQUILIBRIA FOR SYMMETRIC 3 × 2 CES / LES PURE EXCHANGE ECONOMIES

This paper explores the existence of multiple equilibria for symmetric 3 individual,2 good CES /LES pure exchange economies.Analytically,we show that there are no more than 5 equilibria in such economies.The number of equilibria varies from 5 to 3 then to 1.We generalize our analytical results of existence of 1,3,5 equilibria for a wide range of parametrizations.We also provide concrete examples of 1,3,5 equilibria with parameter zones specified.     

EXISTENCE THEOREM ABOUT MULTIPLE POSITIVE SOLUTIONS TO p-LAPLACIAN BOUNDARY VALUE PROBLEM

In this paper,we apply a fixed point theorem to verify the existence of multiple positive solutions to a p-Laplacian boundary value problem.Sufficient conditions are established which guarantee the existence of multiple positive solutions to the problem.     

可解内生生育率的C-K模型

Abstract. In this paper,a C-K model with solvable endogenous fertility under the strongly addi-tive utility function is presented. The discrimination conditions of the existence of the nonzerosteady states are given. Under a kind of utility function and production function,we prove thatthese conditions are satisfied and the economy at least has an optimal growth path. The position-al relationship of the multiple steady states on the plane is discussed when multiple steady statesand multiple growth paths exist. By numerical analysis ,the fertility decreses with the per capitacapital and per capita consumption increasing and increases with the per capita capital and percapita consumption decreasing on the economic growth path are obtained.     

EXISTENCE AND ITERATIVE APPROXIMATIONS OF BOUNDED POSITIVE SOLUTIONS TO A NONLINEAR NEUTRAL DIFFERENTIAL EQUATION

In this paper,we consider a nonlinear neutral differential equation.By the Schauder fixed point theorem,some sufficient conditions are obtained to ensure the existence of uncountably many bounded positive solutions.In addition,we give the iterative approximation sequences with errors for these positive solutions and establish some error estimates between the approximate and the positive solutions.     

POSITIVE SOLUTIONS TO A NONHOMO- GENEOUS NONAUTONOMOUS SECOND- ORDER BOUNDARY VALUE PROBLEM

The existence of multiple positive solutions is studied for a nonlinear nonauto- nomous second-order boundary value problem with nonhomogeneous boundary con- ditions. In order to describe the growth behaviors of nonlinearity on some bounded sets, two height functions are introduced. By considering the integrals of the height functions and applying the Krasnosel＇skii fixed point theorems on a cone, several new results are proved.     

带$p$-Laplacian的四阶四点奇异边值问题的正解

In this paper, we consider the existence of positive solutions for the singular fourthorder four point boundary value problem with p-Laplacian operator. By using the fixed point theorem of cone expansion and compression, the existence of multiple positive solutions is obtained.     

Multibump solutions for discrete periodic nonlinear Schrödinger equations

In this paper, we study the existence of multibump solutions for discrete nonlinear Schrödinger equations with periodic potentials. We first reduce the existence of multibump homoclinic solutions to the existence of an isolated homoclinic solution with a nontrivial critical group. Then, we study the existence of homoclinics with nontrivial critical groups for both superlinear and asymptotically linear discrete periodic nonlinear Schrödinger equations, and we provide simple sufficient conditions for the existence of homoclinics with nontrivial critical groups in the positive definite case. As an application, we get, without any symmetry assumptions, infinitely many geometrically distinct homoclinic solutions with exponential decay at infinity.     

Homoclinics and chaotic behaviour for perturbed second order systems

This paper deals with perturbed dynamical systems of the form: $ - \ddot u + u = \nabla V\left( u \right) + \varepsilon \nabla _u W\left( {t,u} \right)$ where u(t)∈Rⁿ(n?1). By means of a variational approach the existence of multibump homoclinics is proved under general assumptions on the Melnikov function. As a particular case, if (W; u) is T-periodic, the existence of approximate and complete Bernoulli shift structures is proved. An application to partial differential equations is also given.     

On zeros of polynomials orthogonal with respect to a quasi-definite inner product on the unit circle

In this paper we present some results concerning the zeros of sequences of polynomials orthogonal with respect to a quasi-definite inner product on the unit circle. We study zero general properties, the existence of sequences with prefixed zeros and some situations concerning the polynomials with multiple zeros.     

Company-wide production planning using a multiple technology DEA approach

In this paper, Data Envelopment Analysis is used to determine the target output levels (and corresponding required inputs) for the multiple facilities under the responsibility of a Top Decision Maker. The proposed approach aims at minimizing the input costs incurred to attain specified total, company-wide output levels. Specific features of the proposed approach are the consideration of multiple technologies, lower and upper bounds on the production levels of each plant and the possibility of shutting down a plant, with the corresponding costs, if necessary. The consideration of multiple technologies, in particular, takes into account the existence of heterogeneity within the company's facilities. In that scenario, grouping all plants within a single technology gives misleading results.     

Solitary wave families of a generalized microstructure PDE

Wave propagation in a generalized microstructure PDE, under the Mindlin relations, is considered. Limited analytic results exist for the occurrence of one family of solitary wave solutions of these equations. Since solitary wave solutions often play a central role in the long-time evolution of an initial disturbance, we consider such solutions here (via normal form approach) within the framework of reversible systems theory. Besides confirming the existence of the known family of solitary waves, we find a continuum of delocalized solitary waves (or homoclinics to small-amplitude periodic orbits). On isolated curves in the relevant parameter region, the delocalized waves reduce to genuine embedded solitons. The new family of solutions occur in regions of parameter space distinct from the known solitary wave solutions and are thus entirely new. Directions for future work are also mentioned.     

Constructing Examples with 5 Equilibria for Symmetric 3 × 2 Ces / Les Pure Exchange Economies

This paper explores the existence of multiple equilibria for symmetric 3 individual, 2 good CES / LES pure exchange economies. Analytically, we show that there are no more than 5 equilibria in such economies. The number of equilibria varies from 5 to 3 then to 1. We generalize our analytical results of existence of 1, 3, 5 equilibria for a wide range of parametrizations. We also provide concrete examples of 1, 3, 5 equilibria with parameter zones specified.     

Solitary-wave families of the Ostrovsky equation: An approach via reversible systems theory and normal forms

The Ostrovsky equation is an important canonical model for the unidirectional propagation of weakly nonlinear long surface and internal waves in a rotating, inviscid and incompressible fluid. Limited functional analytic results exist for the occurrence of one family of solitary-wave solutions of this equation, as well as their approach to the well-known solitons of the famous Korteweg–de Vries equation in the limit as the rotation becomes vanishingly small. Since solitary-wave solutions often play a central role in the long-time evolution of an initial disturbance, we consider such solutions here (via the normal form approach) within the framework of reversible systems theory. Besides confirming the existence of the known family of solitary waves and its reduction to the KdV limit, we find a second family of multihumped (or N-pulse) solutions, as well as a continuum of delocalized solitary waves (or homoclinics to small-amplitude periodic orbits). On isolated curves in the relevant parameter region, the delocalized waves reduce to genuine embedded solitons. The second and third families of solutions occur in regions of parameter space distinct from the known solitary-wave solutions and are thus entirely new. Directions for future work are also mentioned.     

The Gauss code problem off the plane

The classical Gauss code problem asks to characterize which cyclic sequences arise as the vertex sequence of the straight-ahead path of a 4-regular graph embedded in the plane This problem is generalized to certain 4 regular graphs in arbitrary surfacesA characterization is given for the existence of a 4-regular graph in a specified surface yielding the specified sequence This characterization is obtained using a generalization of Shank's left-right paths     

A dirichlet problem for an equation of mixed type with a discontinuous coefficient

Summary A Dirichlet problem for an equation of mixed type with a discontinuous coefficient is considered for a rectangle. In one part of the rectangle, Laplace's equation is specified while the wave equation is specified in the other part. The questions of existence, non-existence, uniqueness and non-uniqueness are discussed.     

Continuation of Functions Representable via Infinitely Multiple Exponentials with Alternating Exponents

For infinitely multiple exponentials with two alternating exponents, we construct continuations to unbounded domains, so that these continuations are the limit functions of sequences of finitely multiple exponentials. We prove that, for different exponents, such a continuation is unique in the class of continuously differentiable functions. We extend the domain of existence of infinitely multiple exponentials. For exponents with the same signs, this domain remains bounded, while for exponents with different signs, it coincides with the number axis.