The finite element method for fractional diffusion with spectral fractional Laplacian

This paper focuses on the finite element method for Caputo-type parabolic equation with spectral fractional Laplacian, where the time derivative is in the sense of Caputo with order in (0,1) and the spatial derivative is the spectral fractional Laplacian. The time discretization is based on the Hadamard finite-part integral (or the finite-part integral in the sense of Hadamard), where the piecewise linear interpolation polynomials are used. The spatial fractional Laplacian is lifted to the local spacial derivative by using the Caffarelli–Silvestre extension, where the finite element method is used. Full-discretization scheme is constructed. The convergence and error estimates are obtained. Finally, numerical experiments are presented which support the theoretical results.     

Li–Yorke sensitive and weak mixing dynamical systems

Akin and Kolyada in 2003 [E. Akin, S. Kolyada, Li–Yorke sensitivity, Nonlinearity 16 (2003), pp. 1421–1433] introduced the notion of Li–Yorke sensitivity. They proved that every weak mixing system (X, T), where X is a compact metric space and T a continuous map of X is Li–Yorke sensitive. An example of Li–Yorke sensitive system without weak mixing factors was given in [M. ?iklová, Li–Yorke sensitive minimal maps, Nonlinearity 19 (2006), pp. 517–529] (see also [M. ?iklová-Mlíchová, Li–Yorke sensitive minimal maps II, Nonlinearity 22 (2009), pp. 1569–1573]). In their paper, Akin and Kolyada conjectured that every minimal system with a weak mixing factor, is Li–Yorke sensitive. We provide arguments supporting this conjecture though the proof seems to be difficult.     

像空间为$l^1$的单位球面上的等距延拓问题

The main result of this paper is to prove Fang and Wang＇s result by another method： Let E be any normed linear space and Vo ： S（E）→ S（l^1） be a surjective isometry. Then V0 can be linearly isometrically extended to E.     

关于对偶扩张拟遗传代数的Kazhdan-Lusztig理论

In order to study the representation theory of Lie algebras and algebraic groups, Cline, Parshall and Scott put forward the notion of abstract Kazhdan-Lusztig theory for quasihereditary algebras. Assume that a quasi-hereditary algebra B has the vertex set Q0 = {1,..., n} such that HomB（P（i）, P（j）） = 0 for i 〉 j. In this paper, it is shown that if the quasi-hereditary algebra B has a Kazhdan-Lusztig theory relative to a length function l, then its dual extension algebra A = .A（B） has also the Kazhdan-Lusztig theory relative to the length function l.     

Shear modulus of two-dimensional foams: The effect of area dispersity and disorder

We use the Surface Evolver to determine the shear modulus G of a dry 2D foam of 2500 bubbles, using both extensional and simple shear. We examine G for a range of monodisperse, bidisperse and polydisperse foams, and relate it to various measures of the structural disorder of each foam. In all cases, the shear modulus of a foam decreases with increasing disorder.     

乘积∏_(k=1)~n(ak~2+bk+c)的平方性

本文证明了乘积∏_(k=1)~n(ak~2+6k+c)(f(x)=ax~2+bx+c∈Z[x]是二次不可约多项式)在n充分大时不是平方数.     

An aggregation framework based on coherent lower previsions: Application to Zadeh’s paradox and sensor networks

The problem of aggregating two or more sources of information containing knowledge about a common domain is considered. We propose an aggregation framework for the case where the available information is modelled by coherent lower previsions, corresponding to convex sets of probability mass functions. The consistency between aggregated beliefs and sources of information is discussed. A closed formula, which specializes our rule to a particular class of models, is also derived. Two applications consisting in a possible explanation of Zadeh’s paradox and an algorithm for estimation fusion in sensor networks are finally reported.     

$(\omega_1)$性质与单值延拓性质

In this note we study the property（ω1）,a variant of Weyl＇s theorem by means of the single valued extension property,and establish for a bounded linear operator defined on a Banach space the necessary and sufficient condition for which property（ω1） holds.As a consequence of the main result,the stability of property（ω1） is discussed.     

高维紧支撑正交对称的小波

基于仿酉矩阵的对称扩充方法,该文提出了一种尺度因子为3的紧支撑高维正交对称小波构造算法.即设φ(x)∈L~2(R~d)是尺度因子为3的紧支撑d维正交对称尺度函数,P(ξ)是它的两尺度符号,p_(0,v)(ξ)为P(ξ)的相位符号.首先提出一种向量的对称正交变换,应用对称正交变换对3~d维向量(p_(0,v)(ξ))_v,v∈E_d的分量进行对称化.通过仿酉矩阵的对称扩充,给出了3~d-1个紧支撑高维正交对称小波构造.这种方法构造的小波支撑不超过尺度函数的支撑.最后给出一个构造算例.     

万有Teichmuller空间各分支边界点的一些几何性质

在对数导数意义下,万有Teichmuller空间T1可表示为无穷多个互不相交的连通分支的并集.本文研究了该模型各分支的几何性质,给出了为e-iθ/（1-e-iθz）为L和Le的公共边界点,且在‖·‖1的意义下,证明了L,L0,Lθ两两公共边界点之间的距离均为2.