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Chinese Annals of mathematics,Series B 2000年第3期21卷 351-358页

作者： YANG HAITAO(department of mathematics, zhejiang university, hangzhou 310027, china.) WU SHAOPING(department of mathematics, zhejiang university, hangzhou 310027, china.) department of mathematics Zhejiang University Hangzhou 310027 China

By making use of Variational method, the authors obtain some results about existence of multiple positive solutions and their asymptotic behavior as the parameter →＋∞ for a semilinear elliptic problem in RN.

关键词： Critical point Asymptotic behavior Concentration

REMARKS ON h-TRANSFORM AND DRIFT

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Chinese Annals of mathematics,Series B 1998年第4期19卷 473-478页

作者： YING JIANGANG (department of mathematics, zhejiang university, hangzhou 310027, china.) zhejiang Univ Dept Math Hangzhou 310027 Peoples R China

The author studies the h-transforms of symmetric Markov processes and corresponding Dirichlet spaces, and also discusses the drift transformation of Fukushima and Takeda’s type[2] and improves their result by a diffe... 详细信息

关键词： Right processes Revuz measures h-transform

Circular β ensembles,CMV representation,characteristic polynomials

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Science china mathematics 2009年第7期52卷 1467-1477页

作者： SU ZhongGen department of mathematics,zhejiang university,hangzhou 310027,china 1. department of mathematics Zhejiang University Hangzhou 310027 China

In this note we first briefly review some recent progress in the study of the circular β ensemble on the unit circle,where β > 0 is a model *** the special cases β = 1,2 and 4,this ensemble describes the joint probability density of eigenvalues of random orthogonal,unitary and sympletic matrices,*** general β,Killip and Nenciu discovered a five-diagonal sparse matrix model,the CMV *** representation is new even in the case β = 2;and it has become a powerful tool for studying the circular β *** then give an elegant derivation for the moment identities of characteristic polynomials via the link with orthogonal polynomials on the unit circle.

关键词： characteristic polynomials circular β ensembles CMV representation moment identity 15A52

Mean size formula of wavelet subdivision tree on Heisenberg group

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Applied mathematics(A Journal of Chinese Universities) 2008年第3期23卷 303-312页

作者： WANG Guo-mao department of mathematics,zhejiang university,hangzhou 310027,china department of mathematics,hangzhou Dianzi university,hangzhou 310018,china. department of mathematics Zhejiang University Hangzhou 310027 China department of mathematics Hangzhou Dianzi University Hangzhou 310018 China

The purpose of this paper is to investigate the mean size formula of wavelet packets （wavelet subdivision tree） on Heisenberg group. The formula is given in terms of the p-norm joint spectral radius. The vector refinement equations on Heisenberg group and the subdivision tree on the Heisenberg group are discussed. The mean size formula of wavelet packets can be used to describe the asymptotic behavior of norm of the subdivision tree.

关键词： Heisenberg group wavelet packets subdivision tree joint spectral radius stability

Rigidity for rational maps with Cantor Julia sets

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Science china mathematics 2008年第1期51卷 79-92页

作者： ZHAI Yu department of mathematics, zhejiang university, hangzhou 310027, china department of mathematics Zhejiang University Hangzhou 310027 China

In this paper, we prove that two rational maps with the Cantor Julia sets are quasicon- formally conjugate if they are topologically conjugate.

关键词： Cantor Julia set rigidity puzzle piece bounded shape quasiconformally conjugate 37F12

Local orthogonal transform for a class of acoustic waveguides

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Progress in Natural Science:Materials International 2007年第10期17卷 1136-1146页

作者： Zhu Jianxin and Li Peng(department of mathematics, zhejiang university, hangzhou 310027, china) department of mathematics Zhejiang University Hangzhou 310027 China

There are some curved interfaces in acoustic waveguides. To compute wave propagation along the waveguides with some marching methods, flattening of the internal interfaces is needed. In this paper, a local orthogonal coordinate transform and an equation transform are constructed to solve the two-dimensional Helmholtz equation for the waveguides bounded by a flat top, a flat bottom and two curved internal interfaces with three layered media. The curved internal interfaces are flattened by the local orthogonal coordinate transform, and the corresponding transformed Helmholtz equation can be solved by some marching methods. This treatment can be extended in multilayered medium waveguides. The one-way reformulation based on the Dirichlet-to-Neumann (DtN) map is then used to reduce the boundary value problem to an initial value problem. Numerical implementation of the resulting operator Riccati equation uses a large range step method to discretize the range variable and a truncated local eigenfunction expansion to approximate the operators. This method is particularly useful for solving long range wave propagation problems in slowly varying waveguides with multilayered medium structure.

关键词： Helmholtz equation local orthogonal transform DtN reformulation marching method internal interface one-way reformulation.

Shape blending of artistic brushstroke represented by disk B-spline curves

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Progress in Natural Science:Materials International 2007年第12期17卷 1501-1507页

作者： Cheng Min1,2 and Wang Guojin1(1. department of mathematics, zhejiang university, hangzhou 310027, china 2. department of mathematics, zhejiang university of Technology, hangzhou 310032, china) department of mathematics Zhejiang University Hangzhou 310027 China 2. department of mathematics Zhejiang University of Technology Hangzhou 310032 China

This paper presents an algorithm for automatically generating in-between frames of two artistic brushstrokes. The basic idea of the algorithm is to represent the two key frames of artistic brushstrokes in disk B-spline curves, and then make blending of their geometric intrinsic variables. Given two key frames of artistic brushstrokes, the skeleton curves can be obtained by certain skeleton-based techniques. After disk B-spline representation of the key frames is generated, interpolation of the intrinsic variables of the initial and the target disk B-spline curves is carried out. Examples show that this method can efficiently create in-between frames of artistic brushstrokes.

关键词： computer aided calligraphy shape blending brushstroke disk B-spline curve skeleton.

Extension of a quantized enveloping algebra by a Hopf algebra

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Science china mathematics 2010年第5期53卷 300-307页

作者： WU ZhiXiang department of mathematics,zhejiang university,hangzhou 310027,china 1. department of mathematics Zhejiang University Hangzhou 310027 China

Suppose that H is a Hopf algebra,and g is a generalized Kac-Moody algebra with Cartan matrix A =(aij)I×I,where I is an index set and is equal to either {1,2,...,n} or the natural number set *** f,g be two mappings from I to G(H),the set of group-like elements of H,such that the multiplication of elements in the set {f(i),g(i)|i ∈I} is *** we define a Hopf algebra Hgf Uq(g),where Uq(g) is the quantized enveloping algebra of g.

关键词： quantum enveloping algebra Hopf algebra Kac-Moody algebra

Strong uniqueness of best approximations in spaces of bounded linear operators

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Science china mathematics 2004年第3期47卷 339-351页

作者： LI Chong HE Jinsu department of mathematics, zhejiang university hangzhou 310027, china department of mathematics, zhejiang Normal university Jinhua 321004, china 1. department of mathematics Zhejiang University 310027 Hangzhou China 2. department of mathematics Zhejiang Normal University 321004 Jinhua China

The present paper is concerned with problems of the strong uniqueness of the best approximation and the characterization of a uniqueness element in operator *** results on the strong uniqueness of the best approximation operatorfrom RS-sets are proved and the uniqueness element of a sun in the compactoperator space from c0 to c0 is characterized by the strict Kolmogorov's *** recent results due to Lewicki and others are extended and improved.

关键词： best approximation operator, RS-set, sun, strong uniqueness, uniqueness element.