按有理函数系展开函数成Fourier级数

In this paper we give some orthogonal system of rational functions on the unit circumference; We obtained the Riemann Lemma and some tests of convergence of Fourier series for this orthogonal system with the poles {α_k}₀^∞ satisfying some conditions, The conditions we obtained are weaker than those established in [2].     

随机中止试验的线性模型中参数估计的几个性质

When sample size is a sequence of r.v., the parametric estimates in linear models are interesting both theoretically and practically. For linear models Y_i=x_iβ+e_i,i=1,2,…where {e_i} are p-dimensional i .i .d.r.v′.s with Ee₁=0. Var e₁=σ²,0<σ²<∞. we consider estimate σ²(v_n) of error variance σ² and least squares estimate β(v_n) of regression coefficient β, here {v_n} is a sequence of r.v. with positve integers larger than P. In this paper some properties of estimates are discussed . Those are unbiasedness, consistency and normality . For σ²(v_n), we also obtain some orders for convergence to normal distribution.     

概率密度的均匀核估计与近邻估计的均方误差

In this paper we consider the Mean Square Error (MSE) of two uaual estimates of density function f(x) at a point x: The uniform kernel estimate f_n(x) and the NN estimate fn(x). we- show that when f is differentiable for sufficiently high order at x. these MSE can be expanded in a form E(f_n(x)-f(x))²=A₁(x)n^-4/5 +A₂(x)n^-1+A₃(x)n^-6/5+…;E(f_n(x)-f(x))²=B₁(x)n^-4/5 +B₂(x)n^-1+B₃(x)n^-6/5+… And if we suitably choose the parameters in f_n and f_n to make A₁(x) and B₁(x)to assume its minimunm value, then we also, have A₂(x) =B₂(x) but A₃(X) differs form B₃(X). This result shows that while the two estimates are not identical with respect to MSE. each one can be superior to the other in various special cases.     

关于可数模空间ε(Ω)的定义

本文给出并证明了[1]中可数模空间ε（Ω）的定义对紧子集列{K_m}^∞_m=1的依赖条件,提出了与紧子集列{K_m}^∞_m=1的选择无关的ε（Ω）的修正定义．     

Heisenberg群上一类左不变LPDO的局部基本解及局部可解性

In this paper it is proved that local fundamental solution exists in some space W^m(H_n) (m∈Z), if the left invariant differential operator on the Heisenberg group H_n satisfies certain condition. The main results are:l.Let L be a left invariant differential operator on H_n. If there exist R≥0, r,s∈R and operators {B_λ|λ∈Γ_R} ∈V^s(Γ_R, M^r) such that, for almost all λ∈Γ_R, B_λ is the right inverse of Ⅱ_λ(L), then there exists E∈W^m(H_n) (when m≥0 or m even) or E∈W^m-1(H_n) (when m<0 and odd) such that LE =δ(near the origie) Where m=min([r],-[2s]-n-2); 2. Let L(W,T) be of the form (3.1). If there exist R≥0 and r,s∈R such that when |λ|≥R,(?) and C_λ≥ C|λ|^x(C>0), then the same conclusion as above holds with m=min(-[2r]-n-2,[-2s]-n-2).     

类2的常数联络黎曼空间

A non-flat Riemannian space V_n is called Riemannian space with constant connection if its Christoffel symbols of the second kind are constant in some coordinate system {xⁱ}. Following G. Vranceanu [3], a Riemannian space V_n with constant connection is said to be of genus p, if the components of the fundamental tensor in the coordinate system {x^{i/sup>} can be written in the form g_ij=c_ijat_a(a=1,…,p) where c_ija are constant, and p is least.In this paper we prove the following}     

多元Szász—Mirkjan算子的一致逼近

本文研究了多元Szása—Mirakjan算子在C_2B(T)中的逼近性质,利用K—泛函,建立了等价的逼近定理.主要结果如下 定理设f∈C_2B(T),0a) ;(ii)‖S_n,m(f)-f‖_∞ =0(n^-a);(iii)a)‖f(x+tφ(x),y)-2f(x,y)+f(x-tφ(x),y)‖_∞ =0(t<     

关于加权位移的酉等价问题

In this paper, we study the unilateral weighted shift which is unitarily equivalent to a Toeplitz operator and prove a similar result to that in [ 1 ] without the hypothesis that the shift must be hyponormal. As a corollary, we show that if the weight sequence {a_n}_n=0^∞ of the shift is convergent, then 1-a_n²=(1-a₀²)ⁿ⁺¹ ?n≥0     

逻辑导数与逻辑积分(Ⅱ)

在[4]中我们对空间LR+q、1≤q≤2,讨论了函数的逻辑导数与积分。例如,建立了下列公式D(1)(I(1)f)=f,I(1)(D(1)f)=f. 但那里的方法不能用于q>2情形。本文是[4]的继续.对2R+q的Walsh-Fourie     

l-群的极小素子群

本文研究l-群的极小素子群,主要证明如下结果:设G是一个l-群.（1）N∈Γ_m（G）,则N=a^⊥当且仅当{P_N^C}是一个归纳集;（2）g∈G⁺,如果g是特殊的,且g的唯一值是原子,则g^⊥∈Γ_m（G）;（3）G∈B_w,Γ₁（C）是原子的当且仅当Γ_m(G）?Γ₁（G）。