检索结果-南通市图书馆

Nash Inequalities for General Symmetric Forms

在线全文

学校读者我要写书评

暂无评论

Acta Mathematica Sinica,English Series 1999年第3期15卷 353-370页

作者： Mufa Chen department of mathematics, Beijing normal university, Beijing 100875, P. R. china department of mathematics Beijing Normal University Beijing P. R. China

This paper deals with the Nash inequalities and the related ones for general symmetric forms which can be very much unbounded. Some sufficient conditions in terms of the isoperimetric inequalities and some necessary conditions for the inequalities are presented. The resulting conditions can be sharp qualitatively as illustrated by some examples. It turns out that for a probability measure, the Nash inequalities are much stronger than the Poincare and the logarithmic Sobolev inequalities in the present context.

关键词： Nash inequality Symmetric form Isoperimetric Inequality Jump process

Estimate of Exponential Convergence Rate in Total Variation by Spectral Gap

在线全文

学校读者我要写书评

暂无评论

Acta Mathematica Sinica,English Series 1998年第1期14卷 9-16页

作者： Chen Mufa department of mathematics, Beijing normal university, Beijing 100875, china 北京师范大学数学系北京

This note is devoted to study the exponential convergence rate in the total variation for reversible Markov processes by comparing it with the spectral gap. It is proved that in a quite general setup, with a suitable restriction on the initial distributions, the rate is bounded from below by the spectral gap. Furthemore, in the compact case or for birth-death processes or half-line diffosions, the rate is shown to be equal to the spectral gap.

关键词： Total variation Spectral gap Markov processes

Relations between Lipschitz functions and convex functions

在线全文

学校读者我要写书评

暂无评论

Science china mathematics 2005年第5期48卷 703-710页

作者： RUAN Yingbin department of mathematics, Fujian normal university, Fuzhou 350007, china Academy of mathematics and Systems Science, Chinese Academy of Sciences, Beijing 100080, china 1. department of mathematics Fujian Normal University 350007 Fuzhou China 2. Academy of mathematics and Systems Science Chinese Academy of Sciences 100080 Beijing China

We discuss the relationship between Lipschitz functions and convex functions. By these relations, we give a sufficient condition for the set of points where Lipschitz functions on a Hilbert space is Frechet differenti... 详细信息

关键词： Lipschitz functions convex functions the Frechet differentiability.

Tests for nonparametric parts on partially linear single index models

在线全文

学校读者我要写书评

暂无评论

Science china mathematics 2007年第3期50卷 439-449页

作者： Ri-quan ZHANG department of Statistics, East china normal university, Shanghai 200062, china department of mathematics, Shanxi Datong university, Datong 037009, china department of Statistics East China Normal University Shanghai 200062China

Tests for nonparametric parts on partially linear single index models are considered in this paper. Based on the estimates obtained by the local linear method, the generalized likelihood ratio tests for the models are established. Under the null hypotheses the normalized tests follow asymptotically the χ2-distribution with the scale constants and the degrees of freedom being independent of the nuisance parameters, which is called the Wilks phenomenon. A simulated example is used to evaluate the performances of the testing procedures empirically.

关键词： local linear method partially linear single index models generalized likelihood ratio test Wilks phenomenon χ 2-distribution 62G10 62G20

在线全文

学校读者我要写书评

暂无评论

Science china(Life Sciences) 2009年第8期52卷 780-788页

作者： YANG Bo1,YANG SuYong2,ZHAO Lun3,YIN LiuHua1,LIU Xu1& AN ShaSha1 1 Laboratory of Psychology,School of Sociology,china university of Political Science and Law,Beijing 102249,china 2 National Key Laboratory of Cognitive Neurosciences and Learning,Beijing normal university,Beijing 100875,china 3 Institute of Language,xuzhou normal university,xuzhou 221116,china Laboratory of Psychology School of Sociology China University of Political Science and Law Beijing 102249 China National Key Laboratory of Cognitive Neurosciences and Learning Beijing Normal University Beijing 100875 China Institute of Language Xuzhou Normal University Xuzhou 221116 China

Inhibitory control dysfunction is regarded as a core feature in *** major objective of this study was to explore the time course of response inhibition in chronic heroin addicts and provide the neurophysiological evidence of their inhibitory control *** amplitudes and latencies of ERP components were studied in fourteen heroin addicts(mean duration of heroin use being(13.54±5.71) years(Mean±SD),average abstinence being((4.67±6.44) months)) and fourteen matched healthy controls with a visual Go/Nogo *** results showed that heroin addicts demonstrated significantly larger Go-N2 amplitudes which results in a decreased N2 Go/Nogo effect,but no statistically significant differences were found between heroin addicts and controls in *** ERP data suggest that fronto-central areas of heroin addicts were impaired during the inhibition process(200-300 ms) and over-activated to *** impaired early process might reflect an abnormal conflict monitoring process in heroin *** results consolidate the inhibitory control dysfunction hypothesis in chronic heroin users.

关键词： heroin addicts events-related potentials inhibitory control conflict monitoring response inhibition

Estimation of Spectral Gap for Markov Chains

在线全文

学校读者我要写书评

暂无评论

Acta Mathematica Sinica,English Series 1996年第4期12卷 337-360页

作者： Chen Mufa department of mathematics Beijing normal university Beijing, 100875 china department of mathematics Beijing Normal University Beijing China

The study of the convergent rate (spectra gap) in the L^2-sense is motivated from several different fields: probability statistics, mathematical physics, computer science and so on and it is now an artive research topic. Based on a new approach (the coupling technique) introduced in [7] for the estimate of the convergent rate and as a continuation of [4],[5],[7-9],[23] and [24], this paper studies the estimate of the rate for time-continuous Markov chains. Two variational formulas for the rate are presented here for the first time for birth-death processes. For diffusions, similar results are presented in an accompany paper [10]. The new formulas enable us to recover or improve the main known results. The connection between the sharp estimate and the corresponding eigenfunction is explored and illustrated by various examples. A previous result on optimal Markovian couplings is also extended in the paper.

关键词： Markov chains Spectral gap Couplings

Moderate deviation for super-Brownian motion with immigration

在线全文

学校读者我要写书评

暂无评论

Science china mathematics 2004年第3期47卷 440-452页

作者： ZHANG Mei department of mathematics, Beijing normal university, Beijing 100875, china department of mathematics, The Central university of Finance and Economics, Beijing 100081, china 1. department of mathematics Beijing Normal University 100875 Beijing China 2. department of mathematics The Central University of Finance and Economics 100081 Beijing China

We prove a moderate deviation principle for a super-Brownian motion with immigration of all dimensions, and consequently fill the gap between the central limit theorem and large deviation principle.

关键词： moderate deviation principle super-Brownian motion with immigration large deviation principle evolution equation

Functional central limit theorem for super α-stable processes

在线全文

学校读者我要写书评

暂无评论

Science china mathematics 2004年第6期47卷 874-881页

作者： HONG Wenmingdepartment of mathematics, Beijing normal university, Beijing 100875, china 1. department of mathematics Beijing Normal University 100875 Beijing China

A functional central limit theorem is proved for the centered occupation time process of the super α-stable processes in the finite dimensional distribution sense. For the intermediate dimensions α < d < 2α (0 < α ≤ 2), the limiting process is a Gaussian process, whose covariance is specified; for the critical dimension d= 2α and higher dimensions d < 2α, the limiting process is Brownian motion.

关键词： super α-stable processes occupation time central limit theorem evolution equation

Uniqueness theorem for algebraic curves on compact Riemann surfaces

在线全文

学校读者我要写书评

暂无评论

Science china mathematics 2007年第5期50卷 683-688页

作者： Yan XU & Min RU department of mathematics, Nanjing normal university, Nanjing 210097, china department of mathematics, university of Houston, Houston, TX 77401, USA 1. department of mathematics Nanjing Normal University Nanjing 210097 China 2. department of mathematics University of Houston Houston TX 77401 USA

In this paper, we prove a uniqueness theorem for algebraic curves from a compact Riemann surface into complex projective spaces.

关键词： uniqueness theorem algebraic curves Riemann surfaces Nevanlinna theory 32H30