弱半单纯Banach代数的完备范数拓扑唯一性

本文证明了弱半单纯Ｂａｎａｃｈ代数的完备范数拓扑在等价意义下的唯一性．     

L-型域上Toeplitz算子代数的广群结构

讨论L-型域上Toeplitz C^*-代数C^*(Ω)所对应广群G的拓扑结构.用Euclid空间加法闭子群的分类方法对G的单位空间M_∞的拓扑结构进行了详细刻画。     

关于(QU)型模糊拓扑群的直积

研究(QU)型模糊拓扑群族直积,证明了任意(QU)型模糊拓扑群族的直积仍是(QU)型模糊拓扑群;研究了(QU)型模糊拓扑群族直积的模糊单位元之重域基的结构,得到了(QU)型模糊拓扑群族直积的一些重要性质.     

Fuzzy拓扑共生预序空间

文[1]给出了研究拓扑空间,邻近空间,一致空间的统一化理论的方法,提出了拓扑共生结构的概念。文[3,4]引入了Fuzzy拓扑共生结构,初步研究了Fuzzy拓扑,Fuzzy邻近结构,Fuzzy一致结构的统一化问题,文[5]讨论了Fuzzy拓扑共生结构生成     

L-fuzzifying拓扑空间范畴和可延L-fuzzy拓扑空间范畴的Galois联络

在完全分配格的格值环境下,提供了L-fuzzifying拓扑结构和可延L-fuzzy拓扑结构相互转化的方法。还进一步研究了L-fuzzifying拓扑空间范畴和可延L-fuzzy拓扑空间范畴之间的关系。文中结果表明,L-fuzzifying拓扑空间范畴和可延L-fuzzy拓扑空间范畴之间存在Galois联络。     

商空间拓扑结构合成

研究了商空间拓扑结构合成方法。首先对商空间理论中的多粒度世界概念进行拓展,证明了基于拓扑结构的多粒度世界按照拓扑粗细关系构成一个完备半序格,并将它称为拓扑粒度格。其次在拓扑粒度格上得出了拓扑向下合成和拓扑向上合成的形式化定义和数学描述,并证明了其数学描述的正确性。最后讨论了这两种合成方法的关系,以实际应用举例得到了求解问题的两个满足一定条件的解集,并讨论了拓扑结构合成方法的意义。     

没有线性结构的极大极小定理与鞍点定理

在没有线性结构的一般集合上引入了函数的一种“凹（凸）”性概念，得到一个没有线性结构的ＦａｎＫｙ不等式；在此基础上，在一般的拓扑空间上建立了极大极小定理，并把著名的鞍点定理推广到没有线性结构的拓扑空间上·     

聚类分析中的对称原则

通过在集合上赋予对称关系 ,作者分析了对称结构与拓扑结构及等价划分的关系 ,指出 :一个对称关系可以唯一决定一种拓扑 ,也可以唯一决定一种等价划分 ;反之 ,赋予一种拓扑结构或等价划分 ,可以定出一种对称关系 .在此基础上 ,作者提供了由拓扑结构进行聚类的方案 ,并设计了聚类划分的数理统计方法     

具有非负Ricci曲率和次大体积增长的完备流形(英文)

本文研究了具有非负Ricci曲率和次大体积增长的完备黎曼流形的拓扑结构问题.利用Toponogov型比较定理及临界点理论,获得了流形具有有限拓扑型的结果,推广了H.Zhan和Z.Shen的定理,并且还证明了该流形的基本群是有限生成的.     

细长体截面绕流中的一种临界状态

应用拓扑分析的方法研究了细长体截面绕流拓扑结构的演变过程·　指出随着细长体背涡的发展,导致截面流场的拓扑结构发生变化,会出现一种临界流动状态·　在这种临界流态下,流场中会出现一种高阶奇点·　这种高阶奇点的指数为-3/2·　这种高阶奇点是结构不稳定的,稍有扰动就会产生分叉,使流场的拓扑结构发生变化·     

Rational energy decay rate for a wave equation with dynamical control

We consider a wave equation with dynamical control. We first establish the rational energy decay rate using a multiplier method. Next, using a spectrum method, we prove that the rational energy decay rate is optimal.     

Bounds on complexity of matrix multiplication away from Coppersmith–Winograd tensors

We present three families of minimal border rank tensors: they come from highest weight vectors, smoothable algebras, and monomial algebras. We analyze them using Strassen's laser method and obtain an upper bound 2.431 on ω. We also explain how in certain monomial cases using the laser method directly is less profitable than first degenerating. Our results form possible paths in the search for valuable tensors for the laser method away from Coppersmith-Winograd tensors.     

Mode matching analysis for wave scattering in triple and pentafurcated spaced ducts

We present solutions to both trifurcated and pentafurcated spaced waveguides using the mode matching (or eigenfunction expansion) method. While the trifurcated problem with mean fluid flow has been solved previously using the Wiener–Hopf technique, we solve this problem to validate and demonstrate our method. We then show how we can easily generalize the method to the pentafurcated problem that has not been solved previously. We observe that mode matching method is easier to derive and generalize than the Wiener–Hopf technique. We also investigate the numerical solution in detail for various geometries to model practical exhaust systems. Copyright © 2015 John Wiley & Sons, Ltd.     

Long‐time behavior of the proper orthogonal decomposition method

We present explicit error bounds concerning the behavior of the proper orthogonal decomposition (POD) method when the data are drawn from long trajectories. We express the error of the POD method in terms of the canonical angle for systems with exponentially decaying behavior. We test our theoretical bounds numerically using a linear parabolic equation. The considerations are motivated by a subdivision algorithm for the computation of invariant measures in discrete dynamical systems using the POD method as a model reduction tool. Copyright © 2011 John Wiley & Sons, Ltd.     

Stochastic Matrix-Free Equilibration

We present a novel method for approximately equilibrating a matrix using only multiplication by the matrix and its transpose. Our method is based on convex optimization and projected stochastic gradient descent, using an unbiased estimate of a gradient obtained by a randomized method. Our method provably converges in expectation and empirically gets good results with a small number of iterations. We show how the method can be applied as a preconditioner for matrix-free iterative algorithms, substantially reducing the iterations required to reach a given level of precision. We also derive a novel connection between equilibration and condition number, showing that equilibration minimizes an upper bound on the condition number over all choices of row and column scalings.     

Minimization by coordinate descent

We examine the minimization of anN-dimensional real-valued function using the coordinate descent method. We impose conditions on the function under which the method converges; furthermore, by specializing our class of functions, we obtain the rate of convergence. We also present some examples from classical approximation theory where this method applies. A computational example is also given.     

Monotone methods and stability results for nonlocal reaction-diffusion equations with time delay

In this paper, we study the applications of the monotone iteration method for investigating the existence and stability of solutions to nonlocal reaction-diffusion equations with time delay. We emphasize the importance of the idea of monotone iteration schemes for investigating the stability of solutions to such equations. We show that every steady state of such equations obtained by using the monotone iteration method is priori stable and all stable steady states can be obtained by using such method. Finally, we apply our main results to three population models.     

A Gauss–Newton Approach for Solving Constrained Optimization Problems Using Differentiable Exact Penalties

We propose a Gauss–Newton-type method for nonlinear constrained optimization using the exact penalty introduced recently by André and Silva for variational inequalities. We extend their penalty function to both equality and inequality constraints using a weak regularity assumption, and as a result, we obtain a continuously differentiable exact penalty function and a new reformulation of the KKT conditions as a system of equations. Such reformulation allows the use of a semismooth Newton method, so that local superlinear convergence rate can be proved under an assumption weaker than the usual strong second-order sufficient condition and without requiring strict complementarity. Besides, we note that the exact penalty function can be used to globalize the method. We conclude with some numerical experiments using the collection of test problems CUTE.     

A Linear Method for the Recovery of Functions Based on Binary Data Completion

We construct a linear recovery method based on binary data completion using the Bessel interpolation formula. We find an asymptotic value of the error of this method, determine its norm, and study its properties.     

Explicit Hybrid Numerical Method for the Allen-Cahn Type Equations on Curved Surfaces

We present a simple and fast explicit hybrid numerical scheme for the motion by mean curvature on curved surfaces in three-dimensional (3D) space. We numerically solve the Allen-Cahn (AC) and conservative Allen-Cahn (CAC) equations on a triangular surface mesh. We use the operator splitting method and an explicit hybrid numerical method. For the AC equation, we solve the diffusion term using a discrete Laplace-Beltrami operator on the triangular surface mesh and solve the reaction term using the closed-form solution, which is obtained using the separation of variables. Next, for the CAC equation, we additionally solve the time-space dependent Lagrange multiplier using an explicit scheme. Our numerical scheme is computationally fast and efficient because we use an explicit hybrid numerical scheme. We perform various numerical experiments to demonstrate the robustness and efficiency of the proposed scheme.