二阶差分边值问题的正解

本文研究了非线性项具有半正定和混合单调性的二阶差分边值问题正解的存在性.利用Krasnosel'skii不动点定理和锥拉伸与锥压缩不动点定理,讨论了二阶半正定非线性差分边值问题以及非线性项具有半正定和混合单调性的特征值问题正解的存在性,给出了这几类差分边值问题的正解存在性定理,改进和推广了具有正定非线性项的二阶差分边值问题的一些结果,并将所得结果应用于一个具体的二阶半正定非线性差分边值问题中.     

一类二阶三点边值问题单调正解的存在性

利用范数形式的锥上不动点定理,研究了一类二阶微分方程三点边值问题单调正解的存在性．分别给出了齐次和非齐次边界条件下的三点边值问题单调正解存在的充分条件,确定了解曲线的凹凸性,并且给出了一个应用实例．     

一类具有非线性边值条件的非线性分数阶微分方程正解的存在性（英文）

本文研究一类非线性分数阶边值问题正解的存在唯一性问题.利用混合单调算子的方法,获得至少一个正解的存在性结果,推广了整数阶边值问题的存在唯一性结果.     

半直线上Riemann-Liouville型奇异分数阶微分方程边值问题的单调迭代方法

运用不动点定理和单调迭代方法研究半直线上Riemann-Liouville型奇异分数阶微分方程边值问题的正解的存在性.在没有上、下解存在的假设下建立了边值问题存在两个正解的结果,构造了逼近正解的迭代格式,该迭代格式便于应用.     

奇异P-Lapace差分方程边值问题正解的存在唯一性

利用混合单调算子不动点定理研究了一维非线性奇异P-Lapace差分方程边值问题,得到P-Lapace差分方程边值问题的存在唯一正解的充要条件.     

一类无穷区间上具有积分边界条件的分数阶微分方程的正解存在性

研究一类无穷区间上具有积分边界条件的分数阶微分方程边值问题.先构造Green函数,并讨论相关性质,再利用压缩映象原理及单调迭代法,讨论此类边值问题的正解存在性,建立了若干正解存在定理.     

非齐次边界条件下两点边值问题单调解的存在性

研究了一类二阶非线性微分方程在非齐次边界条件下的两点边值问题单调解的存在性.运用锥拉伸与锥压缩不动点定理,分别得到了边值问题单调递增正解和单调递减负解存在的充分条件.     

一类具p-Laplacian算子的多点边值问题单调迭代正解的存在性

利用单调迭代的方法得到了一类具p-Laplacian算子的多点边值问题单调迭代正解的存在性,同时也得到了解的相应迭代序列.     

半直线上具有p-Laplacian算子的Sturm-Liouville型脉冲边值问题的单调迭代正解

利用单调迭代方法得到了半直线上具有p-Laplacian算子的脉冲微分方程边值问题单调迭代正解的存在性,同时也给出了解的相应迭代序列.     

奇异微分方程和差分方程Sturm-Liouville边值问题正解的存在唯一性

利用混合单调算子,研究了微分方程和差分方程的Sturm-Liouville边值问题,得到了一个正解存在唯一的充分条件.     

Estimation of the measure of the image of the ball

Under study is the class of ring Q-homeomorphisms with respect to the p-module. We establish a criterion for a function to belong to the class and solve a problem that stems from M. A. Lavrentiev [1] on the estimation of the measure of the image of the ball under these mappings. We also address the asymptotic behavior of these mappings at a point.     

On the distributions of the ratios of the extreme roots to the trace of the Wishart matrix

In this paper, the authors cosider the derivation of the exact distributions of the ratios of the extreme roots to the trace of the Wishart matrix. Also, exact percentage points of these distributions are given and their applications are discussed.     

On the rational approximation of the sum of the reciprocals of the Fermat numbers

Let $\mathcal{G}(z):=\sum_{n\geqslant0} z^{2^{n}}(1-z^{2^{n}})^{-1}$ denote the generating function of the ruler function, and $\mathcal {F}(z):=\sum_{n\geqslant} z^{2^{n}}(1+z^{2^{n}})^{-1}$ ; note that the special value $\mathcal{F}(1/2)$ is the sum of the reciprocals of the Fermat numbers $F_{n}:=2^{2^{n}}+1$ . The functions $\mathcal{F}(z)$ and $\mathcal{G}(z)$ as well as their special values have been studied by Mahler, Golomb, Schwarz, and Duverney; it is known that the numbers $\mathcal {F}(\alpha)$ and $\mathcal{G}(\alpha)$ are transcendental for all algebraic numbers α which satisfy 0<α<1. For a sequence u, denote the Hankel matrix $H_{n}^{p}(\mathbf {u}):=(u({p+i+j-2}))_{1\leqslant i,j\leqslant n}$ . Let α be a real number. The irrationality exponent μ(α) is defined as the supremum of the set of real numbers μ such that the inequality |α?p/q|<q ^?μ has infinitely many solutions (p,q)∈?×?. In this paper, we first prove that the determinants of $H_{n}^{1}(\mathbf {g})$ and $H_{n}^{1}(\mathbf{f})$ are nonzero for every n?1. We then use this result to prove that for b?2 the irrationality exponents $\mu(\mathcal{F}(1/b))$ and $\mu(\mathcal{G}(1/b))$ are equal to 2; in particular, the irrationality exponent of the sum of the reciprocals of the Fermat numbers is 2.     

Refinement of the asymptotics of the power of the quantile test

One investigates the asymptotic properties of the quantile test, similar to the properties of the Pearson's chi-square test of fit.Translated from Zapiski Nauchnykh Seminarov Leningradskogo Otdeleniya Matematicheskogo Instituta im. V. A. Steklova AN SSSR, Vol. 153, pp. 5–15, 1986.The author is grateful to D. M. Chibisov for useful remarks.     

On the approximation of positive operators and the behaviour of the spectra of the approximants

LetT be a positive linear operator on the Banach latticeE and let (S _n ) be a sequence of bounded linear operators onE which converge strongly toT. Our main results are concerned with the question under which additional assumptions onS _n andT the peripheral spectra (S _n ) ofS _n converge to the peripheral spectrum (T) ofT. We are able to treat even the more general case of discretely convergent sequences of operators.