Hardy和Littlewood的一个三角和

本文对Hardy和Littlewood考虑的一个有限三角和做了进一步地研究.通过充分运用Chebyshev多项式和Möbius函数的性质，建立了该有限三角和的一个有趣的恒等式，并得到了一个精确的渐近公式.     

形式三角矩阵环的Gorenstein遗传性和FP-内射性

我们研究了形式三角矩阵环上模的Gorenstein(半遗传)遗传性,有限表现性和FP-内射性.给出了形式三角矩阵环是Gorenstein(半遗传)遗传的充要条件,并得出了形式三角矩阵环是n-FC环的充分条件.     

一个模糊层次分析法在方案排序中的应用

给出了一个模糊层次分析法(FAHP).该方法的决策矩阵的元素为三角模糊数.结合三角模糊数比较的可能度理论,提出了一个基于模糊层次分析法的有限方案决策方法,最后的实例说明方法的有效性和合理性.     

McCoy-Orrick恒等式的注记

使用复分析方法研究有限三角和与有限三角交错和,从而给出了McCoy-Orrick恒等式的另一种推广.     

环的弱整体维数和CM-自由性

设环R的弱整体维数有限.本文证明R是强CM-自由的.作为应用,本文得到一些同伦范畴和相对导出范畴的三角等价和紧生成性.当R 弱整体维数不超过1时,本文完全分类了这些等价范畴中的可定义子范畴,并说明这些等价的范畴在von Neumann正则环上满足Telescope猜想.同时将一个广义Grothendieck对偶型的三角...     

形式三角矩阵环上的有限表示模

形式三角矩阵环,又称广义三角矩阵环,这类环及其上的模在环模理论中扮演着重要的角色.本文对形式三角矩阵环上的有限表示模进行了一些探讨.     

Hom-Hopf代数的对极和Drinfel'd偶

本文证明了带有等价Hom- 范畴的Hom- 双代数是Hom-Hopf 代数, 在基本结构定理成立的前提下, 构造了对极使其成为Hom-Hopf 代数. 研究了拟三角Hom-Hopf 代数的对极, 并给出了Hom-Hopf 代数的Radford 公式. 最后, 对有限维Hom-Hopf 代数, 引入了Drinfel''d 偶的概念, 同时证明了Drinfel''d 偶是拟三角Hom-Hopf 代数.     

小区间上某种三角和的估计

利用Vaughan恒等式,对小区间上的线性素变数三角和问题进行了研究,得到了在满足一定条件下这类三角和的一个定量上界估计,推广了相关结果.     

Koszul微分分次模

引入了Koszul微分分次模的概念. 给定Koszul微分分次代数上的一个下有界的微分分次模, 如果这个模到平凡模的Ext-\!群是有界的分次空间, 则它必定包含一个微分分次子模, 其在适当的截断和移位下是Koszul微分分次模; 这样的模还可以通过一系列Koszul微分分次模来逼近(参见本文推论3.6). 设$A$是一个Koszul微分分次代数, $D^c(A)$是微分分次右$A$-\!模范畴的导出范畴中由对象$A_A$生成的满三角子范畴. 如果平凡微分分次模$k_A$落在范畴$D^c(A)$中, 则三角范畴$D^c(A)$的标准$t$-\!结构的中心, 作为Abel范畴, 与某个有限维代数上的有限生成模范畴对偶. 进一步, 可推得三角范畴$D^c(A)$等价于它的标准$t$-\!结构的中心的有界导出范畴.     

两类整环上的上三角矩阵群(Ⅰ)

本文从两类整环上的二阶上三角矩阵入手,构造了两个3元生成的亚Abel群,给出了它们的清晰结构,研究了它们的剩余有限性质:一,证明了其中一个无限秩的亚Abel群是剩余有限p-群,这里p是任意素数.二,证明了另一个有限秩的亚Abel群没有这种整齐的剩余有限性质,尽管其结构要简单得多.本文的结果表明,无限可解群里秩的有限性条件对群的剩余有限性具有很大的影响.如何把本文的研究推广到高阶矩阵群,是值得进一步探索的问题.     

The distribution function inequality for a finite sum of finite products of Toeplitz operators

A generalized area function associated with a finite sum of finite products of Toeplitz operators is introduced. A distribution function inequality is established for the generalized area function. By using the distribution function inequality, we characterize when a finite sum of finite products of Toeplitz operators on the Hardy space is a compact perturbation of a Toeplitz operator.     

Polynomials of special form over a finite field with an exact value of the trigonometric sum

We present an explicit construction for polynomials of special form over a finite field whose trigonometric sum is exactly known.     

The finite sum of finite products of Toeplitz operators on the polydisk

A limit theorem is established for a finite sum of finite products of Toeplitz operators on the Hardy space of the polydisk. As a consequence we show that the product of six Toeplitz operators with pluriharmonic symbols is compact iff the product equals zero iff one of these Toeplitz operators equals zero.     

Weighted divisor sums and Bessel function series, IV

One fragment (p.?335) published with Ramanujan??s Lost Notebook contains two formulas, each involving a finite trigonometric sum and a doubly infinite series of Bessel functions. The identities are connected with the classical circle and divisor problems, respectively. This paper is devoted to the first identity. First, we obtain a generalization in the setting of Riesz sums. Second, we prove a trigonometric analogue.     

Toeplitz products with pluriharmonic symbols on the Hardy space over the ball

On the Hardy space over the unit ball in Cn, we consider operators which have the form of a finite sum of products of several Toeplitz operators. We study characterizing problems of when such an operator is compact or of finite rank. Some of our results show higher-dimensional phenomena.     

Estimates from above of certain double trigonometric sums

In this paper we consider double trigonometric sums. Expressions of this type appear in some problems of quantum chaos and number theory. We are interested in rotation numbers of bounded type. We prove a uniform linear bound on double trigonometric sums along the subsequence of denominators of the continued fraction. The proof uses elementary techniques and the analysis of cancellations in sums of certain oscillatory functions over rotations. We also include a proof of a result on discrepancy for rotations of bounded type and in the Appendix we give an elementary proof of a result by Hardy and Littlewood.     

On the summation of Schlömilch's series

ABSTRACT

Schlömilch's series is named after the German mathematician Oscar Xavier Schlömilch, who derived it in 1857 as a Fourier series type expansion in terms of the Bessel function of the first kind. However, except for Bessel functions, here we consider an expansion in terms of Struve functions or Bessel and Struve integrals as well. The method for obtaining a sum of Schlömilch's series in terms of the Bessel or Struve functions is based on the summation of trigonometric series, which can be represented in terms of the Riemann zeta and related functions of reciprocal powers and in certain cases can be brought in the closed form, meaning that the infinite series are represented by finite sums. By using Krylov's method we obtain the convergence acceleration of the trigonometric series.     

Study of some trigonometric series

In this paper we generalize a result due to Hardy. We present a simple example of an everywhere divergent trigonometric series over the squares of the positive integers with coefficients which tend to zero.Translated from Matematicheskie Zametki, Vol. 13, No. 4, pp. 481–492, April, 1973.