查询词典 fixed point theorem

In this thesis, we firstly introduce several class of discrete-time neural network models and the research progress of the neural networks. By Schauder fixed-point principle we prove the existence of an equilibrium (i.e. a fixed point) of a discrete-time neural network with generalized input-output function and by using the converse theorem of Lyapunov function we study the uniformly asymptotical stability of equilibrium in this discrete-time neural network with variable weight and give some sufficient conditions that guarantee the stability of it.

本文首先介绍了几类离散神经网络模型的由来及其研究概况，利用Schauder不动点原理证明了一类具有广义输入输出函数的离散神经网络模型平衡点的存在性，利用Lyapunov函数逆定理给出了这类离散神经网络模型在时变权值下的一致渐近稳定性的充分条件。

Tan and Xu [1] had proved the theorem on convergence of Ishikawa iteration processes of asymptotically nonexpansive mapping on a compact convex subset of a uniform convex Banach space , Then Liu Qihou [3] presents the necessary and sufficient conditions for the Ishikawa iteration of asymptotically quasi-nonexpansive mapping with an error member on a Banach space convergent to a fixed point . Xu and Noor [5] had proved the theorem on convergence of three-step iterations of asymptotically nonexpansive mapping on nonempty closed, bounded and convex subset of uniformly convex Banach space.

Tan和Xu已经证明了建立在一致凸Banach空间紧凸子集上的渐进非扩张映射的Ishikawa迭代序列的收敛原理，随之，刘齐侯又阐述了Banach空间上渐进准非扩张映射T的具误差的Ishikawa迭代序列收敛于T的不动点的充分必要条件；之后，Xu和Noor也证明了定义在一致凸Banach空间某非空有界闭凸子集上的渐进非扩张映射的三步迭代序列的收敛原理。

The model in this paper takes the form as belowThe main contents and results in this paper are as follows:In section 1, we state our main analytical results on equilibria of the above system. First, several sufficient conditions for coexistence of the steady-state are given by the standard fixed-point index theory in cone. Second, the global structure of the coexistence solutions and their local stability are established by using bifurcation theory. Third, the multiplicity, uniqueness and stability of positive steady-state solutions to this system are derived by means of perturbation theory of eigenvalues, standard regularity theory, Sobolev embedding theorem and fixed-point index theory.

本文主要有两章内容：第一章研究了该模型正平衡解的性质，可分为三部分：第一部分运用极值原理、上下解方法和锥映射不动点指标理论得到正平衡解存在的充分条件；第二部分利用分歧理论给出了平衡态系统正分歧解的结构，并讨论了局部分歧解的稳定性；第三部分利用特征值扰动理论、标准椭圆正则化理论、Sobolev嵌入定理及指标理论讨论了正平衡解的多重性、唯一性及稳定性，并讨论了参数对解的影响。

In the first chapter (1.1.1)-(1.1.4) is studied by means of fixed point index theorem, not only the existence theorem is obtained, but the multiplicity is also obtained.

本文第一章利用这一理论研究方程(1.1.1)-(1.1.4)的正周期解问题，与已有研究成果相比，本章不仅获得了该类方程的正周期解的存在性定理又获得了正周期解的多解性定理，并将所取得的结论应用于一些具有实际背景的方程。

As we all know,there is one Simson line at any point on the circumference of triangles,but in this paper, LHP theorem shows that the above conclusion is not correct for any quadrilateral pyramid in three-dimensional space and also during proving LHP theorem,fixed value theorem is proved,at the same time,one guess about the point H and point P on circumscribed sphere of tetrahedron has been concluded.

众所周知，三角形的外接圆周上任一点存在一条 simson 线，而 LHP 定理则指出对于正四面体该结论是不能推广到三维空间上的，并且在论证 LHP 定理的过程中得出了定值定理，同时作为一般四面体的外接球球面上的 H 点、P 点的分布，给出了一个猜想。

By applying a fixed pointed theorem for condesing maps, the sufficient conditions of controllability are given. This method is based on integral expression of solutions, the problem can be converted info fixed point problem of single-valued integral operators.

利用凝聚映射的不动点定理给出了一类发展包含的可控性的充分条件，处理问题的方法是基于解的积分表示，将所讨论的问题转化为集值积分算子的不动点问题。

At first, using fixed point theorem, we establish the sufficient conditions which guarantee the existence, uniqueness, uniform stability of periodic solutions for the equations.

首先，我们利用不动点定理，建立了保证该类方程周期解的存在性、唯一性及一致稳定性的充分条件。

InSection 2,we give several sufficient conditions for the existence of one solution,multiplesolutions and infinitely many solutions of the Sturm-Liouville bvps via the generalizedpolar coordinates.Then in Section 3,the existence of positive solutions are proved undersuperlinearity,sublinearity and many other conditions by a fixed point theorem in cones.Our results have generalized those in many articles.A detailed discussion of periodic solu-tions of a kind of functional differential equations with high-order Laplacian-like operatorcan be found in Section 4 and this subject has not been studied before.

在第二节，我们定义了一种新的坐标变换-广义极坐标，并利用它讨论了p-Laplacian算子和Laplacian-型算子的Sturm-Liouville边值问题，分别得到了存在一个解、多个解、无穷多个解的多个充分条件；第三节研究p-Laplacian算子的Sturm-Liouville边值问题正解的存在性与多重性，采用的是锥上的不动点定理，全面推广了这一方面已有的结果；对目前研究较少的高维Laplacian-型算子及带有Laplacian-型算子的泛函微分方程的周期解问题，我们在第四节做了一些研究，这也是拓扑方法的一个应用。

By using the Krasnoselskii fixed point theorem, an existence result of two positive solutions is obtained under suplinear condition and sublinear condition.

讨论一类四阶非线性微分方程组Dirichlet边值问题正解的存在性，利用Krasnoselskii不动点定理得到这类边值问题在超线性和次线性条件下至少存在两个正解。

Chapter 2 discusses the BVP of non self-adjoint nonlinear second order difference equations by applying matrix theory and Krasnoselskii fixed point theorem.

第二章利用矩阵理论与Krasnoselskii不动点定理，研究了一类非自共轭非线性二阶差分方程的边值问题。

According to the clear water experiment, aeration performance of the new equipment is good with high total oxygen transfer coefficient and oxygen utilization ratio.

曝气设备的动力效率在叶轮转速为120rpm～150rpm时取得最大值，此时氧利用率和充氧能力也具有较高值。

The environmental stability of that world - including its crushing pressures and icy darkness - means that some of its most famous inhabitants have survived for eons as evolutionary throwbacks, their bodies undergoing little change.

稳定的海底环境─包括能把人压扁的压力和冰冷的黑暗─意谓海底某些最知名的栖居生物已以演化返祖的样态活了万世，形体几无变化。