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Acta Mathematica Scientia 2005年第3期25卷 439-448页

作者：房艮孙叶培新 school of mathematical sciences beijing normal university school of mathematical sciences and LPMC Nankai university

The order of computational complexity of all bounded linear functional ap proximation problem is determined for the generalized Sobolev class Wp?（Id）, Nikolskii class H|∞k（Id） in the worst （deterministic）, stochastic and average case setting, from which it is concluded that the bounded linear functional approximation problem for the classes Wp?（Id） and H∞k（Id） is intractable in worst case setting, but is tractable with respect to stochastic and average case setting.

关键词： worst (deterministic) case stochastic case average case setting bounded linear functional error estimate

The relative generalized Hamming weight and the semilinear equivalence of codes

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Science china(Information sciences) 2011年第4期54卷 787-794页

作者： LIU ZiHui 1 & WANG Jie 2 1 Department of Mathematics,beijing Institute of Technology,beijing 100081,china 2.school of mathematical sciences,beijing university,beijing 100871,china 1. Department of Mathematics Beijing Institute of Technology Beijing 100081 China2. School of Mathematical Sciences Beijing University Beijing 100871 China

Certain equivalent conditions are given for the semilinear equivalence of linear codes by using the relative generalized Hamming weight and the value function.

关键词： value function semilinear equivalence support weight relative generalized Hamming weight

Romanoff theorem in a sparse set

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Science china Mathematics 2010年第9期53卷 2195-2202页

作者： CHEN Yong-Gao school of mathematical sciences,Nanjing normal university,Nanjing 210046,china 1. school of mathematical sciences Nanjing Normal University Nanjing 210046 China

Let A be any subset of positive integers,and P the set of all positive *** of our results are:(a) the number of positive integers which are less than x and can be represented as 2k + p(resp.p-2k) with k ∈ A and p ∈ P is more than 0.03A(log x/log 2)π(x) for all sufficiently large x;(b) the number of positive integers which are less than x and can be represented as 2q + p with p,q ∈ P is(1 + o(1))π(log x/log 2)π(x).Four related open problems and one conjecture are posed.

关键词： Romanoff theorem Polignac conjecture asymptotic density

Relative n-widths of periodic convolution classes with NCVD-kernel and B-kernel

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Science china Mathematics 2010年第1期53卷 165-172页

作者： YANG Wei & LIU YongPing school of mathematical sciences,beijing normal university Laboratory of Mathematics and Complex Systems,Ministry of Education,beijing 100875,china 1. school of mathematical sciences Beijing Normal University Laboratory of Mathematics and Complex Systems Ministry of Education Beijing 100875 China

In this paper,we consider the relative n-widths of two kinds of periodic convolution classes,Kp(K) and Bp(G),whose convolution kernels are NCVD-kernel K and B-kernel G. The asymptotic estimations of Kn(Kp(K),Kp(K))q a... 详细信息

关键词： relative n-width periodic convolution class NCVD-kernel B-kernel

Weighted estimates for commutators of singular integral operators with non-doubling measures

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Science china Mathematics 2007年第11期50卷 1621-1641页

作者： Guo-en HU~1 Da-chun YANG~(2+) Dong-yong YANG~2 1 Department of Applied Mathematics,university of Information Engineering,Zhengzhou 450002,china 2.school of mathematical sciences,beijing normal university,beijing 100875,china Department of Applied Mathematics University of Information Engineering Zhengzhou 450002 China school of mathematical sciences Beijing Normal University Beijing 100875 China

Letμbe a nonnegative Radon measure on R^d which only satisfiesμ(B(x,r))≤C_0r^n for all x∈R^d,r>0,and some fixed constants C_0>0 and n∈(0,d].In this paper,some weighted weak type estimates with A_(p,(log L)~σ)~ρ(μ) weights are established for the commutators generated by Calder■n-Zygmund singular integral operators with RBMO(μ) functions.

关键词： non-doubling measure weight singular integral operator commutator

Global Existence of Classical Solutions for Some Oldroyd-B Model via the Incompressible Limit

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Chinese Annals of Mathematics,Series B 2006年第5期27卷 565-580页

作者： Zhen LEI school of mathematical sciences, Fudan university, Shanghai 200433, china school of Mathematics and Statistics, Northeast normal university, Changchun 130024, china. school of mathematical sciences Fudan University Shanghai 200433 China school of Mathematics Statistics Northeast Normal University Changchun 130024 China

In this paper, we prove local and global existence of classical solutions for a system of equations concerning an incompressible viscoelastic fluid of Oldroyd-B type via the incompressible limit when the initial data ... 详细信息

关键词： Incompressible limit Global existence Oldroyd model

Finite Groups in Which Sylow normalizers Admit Supplements

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Acta Mathematica Sinica,English Series 2007年第3期23卷 417-422页

作者： Tian Ze LI school of mathematical sciences,Peking university,beijing 100871,P.R.china school of mathematical sciences Peking University Beijing 100871 P. R.China

For a group G and a subgroup M of G,we say that a subgroup A of G is a supplement toM in G,if G=*** prove that a finite group in which every Sylow normalizer admits a nilpotentsupplement is *** particular we confirm a... 详细信息

关键词： Sylow normalizer Supplement Wreath product

New fossil elaterids(Insect:Coleoptera:Polyphaga:Elateridae) from the Middle Jurassic of Inner Mongolia,china

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Progress in Natural Science:Materials International 2009年第10期19卷 1433-1437页

作者： Huali Chang,Yunyun Zhao,Dong Ren College of Life Science,capital normal university,beijing 100048,china [a]College of Life Science Capital Normal University Beijing 100048 China

A new genus with a new species of fossil elaterid,Paraprotagrypnus superbus *** ***.,from the Middle Jurassic Jiulongshan Formation in Daohugou Village(N41°18.9790,E119°14.3180),Shantou Township,Ningcheng County,Inner Mongolia,china is described and *** genus Paraprotagrypnus belongs to the family of Elateridae,subfamily of Protagrypninae and tribe of *** primitive characters of the new genus and new species shed light on the ages between the Jiulongshan Formation in Inner Mongolia and the Yixian Formation in the western Liaoning Province of *** habitat of the new species is briefly discussed.

关键词： Elateridae New genus Paraprotagrypnus superbus sp.nov. Middle Jurassic Jiulongshan Formation china

THE REGULARITY OF THE FREE BOUNDARY FOR STRIKE RESET OPTION

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Acta Mathematica Scientia 2010年第5期30卷 1721-1729页

作者：杨舟 school of mathematical sciences South China Normal University

A strike reset option is an option that allows its holder to reset the strike price to the prevailing underlying asset price at a moment chosen by the holder. The pricing model of the option can be formulated as a parabolic variational inequality and the optimal reset strategy is the free boundary. The smoothness of the free boundary in some cases was showed in our article published in JDE. We would prove its smoothness in the other case in this paper by a generalized comparison principle for the variational inequality.

关键词： strike reset option free boundary variational inequality the comparison principle

Structure of augmentation quotients of finite homocyclic abelian groups

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Science china Mathematics 2007年第9期50卷 1280-1288页

作者： Guo-ping TANG school of mathematical sciences,Graduate university of Chinese Academy of sciences,beijing 100049,china 1. school of mathematical sciences Graduate University of Chinese Academy of Sciences Beijing 100049 China

Let G be a finite abelian group and its Sylow p-subgroup a direct product of copies of a cyclic group of order p r , i.e., a finite homocyclic abelian group. Let Δ n (G) denote the n-th power of the augmentation ideal Δ(G) of the integral group ring ?G. The paper gives an explicit structure of the consecutive quotient group Q n (G) = Δ n (G)/Δ n+1(G) for any natural number n and as a consequence settles a problem of Karpilovsky for this particular class of finite abelian groups.

关键词： integral group ring augmentation ideal consecutive quotient of augmentation ideal 16S34 20C05