不变测试及其计算

用统计方法研究混沌动力系统的需要藉助不变测度理论。本文通过引进Ｆｒｏｂｅｎｉｕｓ－Ｐｅｒｒｏｎ算子，概述了一类绝对连续不变测度的存在条件与计算现状。     

A local refinement purely meshless scheme for time fractional nonlinear Schrodinger equation in irregular geometry region

A local refinement hybrid scheme(LRCSPH-FDM)is proposed to solve the two-dimensional(2D)time fractional nonlinear Schrodinger equation(TF-NLSE)in regularly or irregularly shaped domains,and extends the scheme to predict the quantum mechanical properties governed by the time fractional Gross-Pitaevskii equation(TF-GPE)with the rotating Bose-Einstein condensate.It is the first application of the purely meshless method to the TF-NLSE to the author’s knowledge.The proposed LRCSPH-FDM(which is based on a local refinement corrected SPH method combined with FDM)is derived by using the finite difference scheme(FDM)to discretize the Caputo TF term,followed by using a corrected smoothed particle hydrodynamics(CSPH)scheme continuously without using the kernel derivative to approximate the spatial derivatives.Meanwhile,the local refinement technique is adopted to reduce the numerical error.In numerical simulations,the complex irregular geometry is considered to show the flexibility of the purely meshless particle method and its advantages over the grid-based method.The numerical convergence rate and merits of the proposed LRCSPH-FDM are illustrated by solving several 1D/2D(where 1D stands for one-dimensional)analytical TF-NLSEs in a rectangular region(with regular or irregular particle distribution)or in a region with irregular geometry.The proposed method is then used to predict the complex nonlinear dynamic characters of 2D TF-NLSE/TF-GPE in a complex irregular domain,and the results from the posed method are compared with those from the FDM.All the numerical results show that the present method has a good accuracy and flexible application capacity for the TF-NLSE/GPE in regions of a complex shape.     

数学家李天岩的治学之路

本文详细地叙述了数学家李天岩的治学之路.     

对应于非半单特征值的一个特征向量-特征值公式（英文）

We prove an eigenvector-eigenvalue formula for the generalized eigenspace of a complex matrix associated to an eigenvalue that has exactly one Jordan block in the Jordan canonical form of the matrix.The new formula generalizes the eigenvector-eigenvalue-identity for normal matrices and extends the formulas for the class of matrices with respect to a semi-simple eigenvalue.     

不变测度及其计算

用统计方法研究混沌动力系统时需要藉助不变测度理论．本文通过引进Ｆｒｏｂｅｎｉｕｓ－Ｐｅｒｏｎ算子，概述了一类绝对连续不变测度的存在条件与计算现状