Existence results of periodic solutions for third‐order nonlinear singular differential equation

Using Green's function for third‐order differential equation and some fixed‐point theorems, i.e., Leray‐Schauder alternative principle and Schauder's fixed point theorem, we establish three new existence results of periodic solutions for nonlinear third‐order singular differential equation, which extend and improve significantly existing results in the literature.     

Fréchet spaces with unconditional base

A nonnormable ?-space possessing an unconditional basis is not necessarily isomorphic to a generalized Köthe space.     

Positive solutions of second-order differential systems with nonhomogeneous boundary conditions

This paper is to investigate the positive solutions of the systems of second-order ordinary differential equations with nonhomogeneous multi-point boundary conditions. By the lower and upper solutions method, Schauder fixed point theorem and fixed point index theory, under certain conditions, it is proved that there exist appropriate regions of parameters in which the problem has at least two, at least one or no positive solution.     

HOMOTOPY PERTURBATION SOLUTION AND PERIODICITY ANALYSIS OF NONLINEAR VIBRATION OF THIN RECTANGULAR FUNCTIONALLY GRADED PLATES

In this paper nonlinear analysis of a thin rectangular functionally graded piate is formulated in terms of von-Karman＇s dynamic equations. Functionaily Graded Material （FGM） properties vary through the constant thickness of the plate at ambient temperature. By expansion of the solution as a series of mode functions, we reduce the governing equations of motion to a Duffing＇s equation. The homotopy perturbation solution of generated Duffing＇s equation is also obtained and compared with numerical solutions. The sufficient conditions for the existence of periodic oscillatory behavior of the plate are established by using Green＇s function and Schauder＇s fixed point theorem.     

On relations between non-Archimedean power series spaces

The power series spaces of finite type, A₁(α), and infinite type, A_∞(α), are the most known and important examples of non-Archimedean nuclear Fréchet spaces. We study when Aπ (α) has a subspace (or quotient) isomorphic to A_q(b).     

四阶差分方程在多点边值条件下解的存在性

运用Schauder不动点定理,考察了边值问题Δ4u(k-1)=g(k,u(k-1),u(k),u(k 1),u(k 2)),k∈Z(1,N)u(0)=A,u(N 1)=B,u(N 2)=C,u(N 3)=D解的存在性.     

Parametric aggregation in ordered weighted averaging

Incorporating further information into the ordered weighted averaging (OWA) operator weights is investigated in this paper. We first prove that for a constant orness the minimax disparity model [13] has unique optimal solution while the modified minimax disparity model [16] has alternative optimal OWA weights. Multiple optimal solutions in modified minimax disparity model provide us opportunity to define a parametric aggregation OWA which gives flexibility to decision makers in the process of aggregation and selecting the best alternative. Finally, the usefulness of the proposed parametric aggregation method is illustrated with an application in metasearch engine.     

可分商空间

考虑无穷维商空间问题，得到一个无穷维Ｂａｎａｃｈ空间Ｘ具有可分的无穷维商空间的几个充分条件．并且还得到：若Ｘ＊含有ｌ１，则或者Ｘ含有ｌ１，或者Ｘ有商空间同构于ｃ０     

Multivalued convexity and optimization: A unified approach to inequality and equality constraints

Multivalued functions satisfying a general convexity condition are examined in the first section. The second section establishes a general transposition theorem for such functions and develops an abstract multiplier principle for them. In particular both convex inequality and linear equality constraints are seen to satisfy the same generalized constraint qualification. The final section examines quasi-convex programmes.