全矩阵环的一类基

设P是一个域,Fij(i,j=1,2,…,n)是全矩阵环Mn(P)中n2个n×n矩阵,且满足FijFkl=δjkFil(i,j,k,l=1,2,…,n),其中δij={1,i=j0,i≠j为Kronecker符号.则或者所有Fij(i,j=1,2,…,n)全为零,或者存在可逆矩阵T∈Mn(P),使得Fij=T-1EijT(i,j=1,2,…,n),其中Eij表示(i,j)位置是1,     

局部(F_4)条件下的两指标Banach空间值鞅的不等式及其在极限定理中的应用

本文中,我们用N~r表示r维正整数格点组成的集合(r≥1,r为整数),N~r中的点用粗写的英文小写字母表示,有时用带下标或不带下标的字母z表示,如n=(n_1,n_2,…,n,)∈N~r, 在N~r中我们定义如下的顺序关系:若n=(n_1,n_2,…,n_r),n'=(n'_1,n'_2,…,n'_r)∈N~r,n≤n'n_i≤n'_i,i=1,2,…,r,若i=(i_1,i_2,…,i_r)j=(j_1,j_2,…,j_r)∈N~r,i相似文献   

Asymptotic Behavior of Oscillatory Solutions of Forced Nonlinear Neutral Delay Differential Equations

§1.　IntroductionThispaperisconcernedwiththeasymptoticbehavioroftheoscillatorysolutionsofnonlin-earforcedneutraldelaydifferentialequationsoftheform[x(t)-∑mi=1pi(t)x(t-τi)]′ ∑nj=1qj(t)f(x(t-σj))=r(t),　t≥t0,(1)wherepi,qj,r∈C([t0,∞),R),τi,σj≥0,i=1,2,…,m;j=1,2,…,n,f∈C(R,R),xf(x)>0forx≠0.Whenpi(t)≡0,i=1,2,…,m,Eq.(1)reducestox(t) ∑nj=1qj(t)f(x(t-σj))=r(t),　t≥t0,(2)whoseasymptoticbehaviorofallsolutionshasbeenstudiedinJ.R.Yan[5].Whenr(t)≡0,f(x)≡xandm=n=1,Eq.(1)reducesto[…     

商模Nφ上解析Toepltz算子的约化子空间

假设Tn表示多圆盘,H2(Tn)表示Tn上的Hardy空间.K表示H2(Tn)中由{(z1φ(z2))f1+…+(z1-φ(zn))fn-1:fi∈H2(Tn),1≤i≤n-1}生成的子模,Nφ表示K在H2(Tn)中的商模.则Nφ上以有限Blaschke乘积ψ(z)为符号的Toeplitz型算子Tψ是可约的.     

论丢番图方程x_1x_2……x_n=t_1~(k_1)……t_l~(k_l)

本文就丢番图方程给出了全部正整数解。有结果:设n和k_1,…,k_1为已知正整数,并设k_j=a_j,m,1 a_j,m,2 … a_j,m,n(m=1,2,…,s_j)为k_j的一切可能的分拆(S_j=(k_j n-1)…(n 1)n/k_j!,j=1,2,…,l),则上述方程(*)的正整数解的形式为,而且只是为所示,其中a_(ij)(j=1,2,…,s_i;i=1,2,…,l)为s_1 s_1 … s_l个任意的正整数。特别地,当l=1,k_1=k时就是A.Schinzel在文[2]中的结果。     

二维Vilenkin型系统的Dirichlet核的加权平均

对二维Vilenkin型系统,我们定义加权平均极大算子T(i.e.Tf:=supn=(n1,n2)∈P2,β-1n1/n2β|Hnf|),并证明此算子是弱(1,1)型、强(p,p)型(1p∞)以及(H,L)型,其中Hnf表示部分和的加权平均,H表示Hardy空间.借用此结果得到序列Hnf是几乎处处收敛于可积函数f.     

Classification of Cartan Matrices of Hyperbolic Type

In the theory of finite dimensional semisimple Lie algebras,it is known thatthe Cartan matrix A=(a_(ij))_i~n, i=1 has the following properties: (1)a_(ii)=2,i=1,…,n; (2)a_(ij)≤0 for i≠j,a_(ij)∈Z; (3)a_(ij)=0 a_(ji)=0. Now if a matrix A=(a_(ij))_i~n,j\j=1 satisfies (1),(2),(3),then A is called     

用Householder变换约化对称带形矩阵为三对角形

对于对称带形矩阵,在[1]中用Givens变换将它约化为三对角形.现在我们用House-holder镜象变换进行约化.给出向量x=(x_1,…,x_(r-1),x_r,x_(r+1),…x_j,x_(j+1),…,x_n)~T,其中x_r,…,x_j不全为零,可以找到一个镜象变换H=I-uu~T/(2k~2),(1)其中向量u的分量u_i=0(i=1,2,…,r-1,j+1,…,n),u_r=x_r+s,u_i=x_i(i=r+1,…,j),s=±(sum from i=r to j x_i~2)~(1/2),2k~2=s~2+x_r s,s的正负号选取与x_r一致,使得Hx=(x…,x_(r-1),-S,0,     

一个有趣的命题及其推论与应用

设X=(x1,x2,……,xk),记函数fi(X)=fi(x1,x2,…xk),又设f(X)为正值函数且其二阶偏导数连续(k≥2),其中i=1,2…n。将形如[(^n∑i=1)fi(X)]/n的函数称为fi(X)(i=1,2…,n)的均值函数;将^n√(^n∏i=1)fi(X)称为fi(X)(i=1,2…,n)的几何均值函数,由fi(X)(i=1,2…,n)的均值函数和fi(X)(i=1,2…,n)的几何均值函数可以得到均值不等式。     

紧支撑正交插值的多小波和多尺度函数

本文给出一类伸缩因子为α的紧支撑正交插值多尺度函数和多小波的构造方法.设{Vj}是尺度函数Φ(x)=[φ1(x),φ2(x),…,φa(x)]T生成的多分辨分析,Vj(?)L2(R)是{a-j/2φ(?)(ajx-k),k∈Z,(?)=1,2,…,a)线性扩张构成的子空间,其插值性是指φ1(x),φ2(x),…,φa(x)满足φj(k+(?)/a)=δk,0δj,e,j,(?)∈{1,2,…,a).当Φ(x)是正交插值的,则多分辨分析的分解或重构系数能用采样点表示而不需要用计算内积的方法产生.基于此,我们建立多小波采样定理,即如果一个连续信号f(x)∈VN,则f(x)=∑i=0a-1∑k∈Zf(k/aN+i/aN+1)φi+1(aNx-k),并给出对应多小波的显式构造公式.更进一步,证明了本文构造的多小波也有插值性.最后,还给出一个构造算例.     

Vector subdivision schemes in (Lp(Rs))r(1 ≤ p ≤∞) spaces

The purpose of this paper is to investigate the refinement equations of the form ψ(x) = ∑α∈Zs a(α)ψ(Mx - α), x ∈ Rs,where the vector of functions ψ=(ψ1,…,ψr)T is in (Lp(Rs))r, 1≤p≤∞,a(α),α∈Zs,is a finitely supported sequence of r × r matrices called the refinement mask, and M is an s × s integer matrix suchthat lim n→∞ M-n = 0. In order to solve the refinement equation mentioned above, we start with a vectorof compactly supported functions ψ0 ∈ (Lp(Rs))r and use the iteration schemes fn := Qnaψ0,n = 1,2,…,where Qa is the linear operator defined on (Lp(Rs))r given by Qaψ:= ∑α∈Zs a(α)ψ(M·- α),ψ∈ (Lp(Rs))r. This iteration scheme is called a subdivision scheme or cascade algorithm. In this paper, we characterize the Lp-convergence of subdivision schemes in terms of the p-norm joint spectral radius of a finite collection of somelinear operators determined by the sequence a and the set B restricted to a certain invariant subspace, wherethe set B is a complete set of representatives of the distinct cosets of the quotient group Zs/MZs containing 0.     

关于伽辽金方法收敛性的判别准则

<正> 伽辽金方法的重要性已为工程数学界所公认.有关它的收敛性的讨论,亦有大量文献与专著.但从算子方程的角度来看,所加的条件还很苛刻.本文则在较一般的条件下给出了伽辽金方法收敛性的一系列判别准则.我们相信,这些结果对于实际应用将是有益的.     

学习理论中基于负相关序列的样本误差估计

给定数据(x1,y1),(x2,y2),…,(xm,ym),考虑一般的损失函数ψ(y-f(x))下,当ψ(z)连续及ξ1=ψ(y1-f(x1)),ξ2=ψ(y2-f(x2)),…,ξm=ψ(ym-f(xm))是一个负相关序列时,本文研究了样本误差估计问题.     

高阶亚纯函数系数微分方程的解及其导数的不动点

研究了高阶线性微分方程f~(k)+A_(k-1)(z)f~(k-1)+…+A_1(z)f′+A_0(z)f=0的非零解f,及其一阶、二阶导数,f~(i)(i=1,2)的不动点性质,这里A_j(z)(j=0,1,…k-1)为亚纯函数,得到了若δ(∞,A_0)>0,且满足max{i(A1),i(A2),…,i(A_(k-1))}相似文献   

格子点上随机场的回归系数的估计问题

<正> §1.引言U.Grenander 研究了随机叙列的回归系数的估计问题,最近 M.Rosenblatt 研究了随机向量叙列的回归系数的估计问题.我们这桌案里研究格子点上随机场的回归系数的估计问题.前二作者所采用的方法是一样的,但是对于随机场而言若采用同一方法则有     

A Class of Constrained Inverse Eigenproblem and Associated Approximation Problem for Symmetric Reflexive Matrices

Let S∈Rn×n be a symmetric and nontrival involution matrix. We say that A∈E R n×n is a symmetric reflexive matrix if AT = A and SAS = A. Let S R r n×n(S)={A|A= AT,A = SAS, A∈Rn×n}. This paper discusses the following two problems. The first one is as follows. Given Z∈Rn×m (m < n),∧= diag(λ1,...,λm)∈Rm×m, andα,β∈R withα<β. Find a subset (?)(Z,∧,α,β) of SRrn×n(S) such that AZ = Z∧holds for any A∈(?)(Z,∧,α,β) and the remaining eigenvaluesλm 1 ,...,λn of A are located in the interval [α,β], Moreover, for a given B∈Rn×n, the second problem is to find AB∈(?)(Z,∧,α,β) such that where ||.|| is the Frobenius norm. Using the properties of symmetric reflexive matrices, the two problems are essentially decomposed into the same kind of subproblems for two real symmetric matrices with smaller dimensions, and then the expressions of the general solution for the two problems are derived.     

具有N策略和负顾客的反馈抢占型M/G/1重试可修排队模型解的渐近行为

研究具有N策略和负顾客的反馈抢占型M/G/1重试可修排队模型的时间依赖解的渐近行为.当初步服务的失效率函数η(x),主要服务的失效率函数μ(x)和修理时间的失效率函数ψ(x)满足0η≤η(x)≤η∞,0μ≤μ(x)≤μ∞,0ψ≤ψ(x)≤ψ∞并且η(x)是Lipschitz连续函数时,证明模型的时间依赖解指数稳定.     

On approximation of smooth functions from null spaces of optimal linear differential operators with constant coefficients

For a real valued function f defined on a finite interval I we consider the problem of approximating f from null spaces of differential operators of the form Ln(ψ) = n ∑ k=0 akψ(k), where the constant coefficients ak ∈ R may be adapted to f . We prove that for each f ∈ C(n)(I), there is a selection of coefficients {a1, ,an} and a corresponding linear combination Sn( f ,t) = n ∑ k=1 bkeλkt of functions ψk(t) = eλkt in the nullity of L which satisfies the following Jackson’s type inequality: f (m) Sn(m )( f ,t) ∞≤ |an|2n|Im|1/1q/ep|λ|λn|n|I||nm1 Ln( f ) p, where |λn| = mka x|λk|, 0 ≤ m ≤ n 1, p,q ≥ 1, and 1p + q1 = 1. For the particular operator Mn(f) = f + 1/(2n) f(2n) the rate of approximation by the eigenvalues of Mn for non-periodic analytic functions on intervals of restricted length is established to be exponential. Applications in algorithms and numerical examples are discussed.