报告题目1：Harish-Chandra modules for divergence zero vector fields on a torus
报告人：    李志强  博士
报告时间：2019年4月2日（周二）16:30—17:00   
报告地点：威廉希尔学术报告厅
报告摘要：The Lie algebra of divergence zero vector fields on a torus is the Lie algebra of the skew derivations over the Laurent polynomials ring. We consider the semidirect product of the Lie algebra of divergence zero vector fields on a torus with the algebra of Laurent polynomials. In this talk, we classify Harish-Chandra modules of the universal central extension of the derived Lie subalgebra of this semidirect product. We prove that such a Harish-Chandra module is a uniformly bounded module or a generalized highest weight module. Furthermore, we classify all the generalized highest weight Harish-Chandra modules.

报告题目2：Rank minimization with applications to image noise removal
报告人：    严辉银  博士
报告时间：2019年4月2日（周二）17:00—17:30   
报告地点：威廉希尔学术报告厅
报告摘要：In this talk, we present a new method for rank minimization problem by utilizing matrixs rank as the regularization term in the energy function. We also prove that the proposed rank minimization model can be solved by hard thresholding operation on the observed matrix singular values. By utilizing image selflsimilarity and image block matching scheme, we further apply the proposed rank minimization method to remove white Gaussian additive noise in images. Gamma multiplicative noise is also removed in logarithm domain. Numerical results illustrate that the proposed rank minimization method can remove noises in images efficiently. Meanwhile, edges and details in images are also preserved.

      李志强，博士，2019年于厦门大学获理学博士学位，主要从事无穷维李代数的表示理论。在国内外重要学术期刊 Journal of Algebra, Pacific Journal of Mathematics,  Science China Mathematics,  Algebra Colloquium 发表学术论文4篇。
      严辉银，博士，2018年12月于兰州大学威廉希尔获理学博士学位，主要从事数值代数、数字图像处理领域研究工作。在国内外重要学术期刊 Information Sciences, Applied Mathematics and Computation，Communications in Computational Physics等发表学术论文4篇。

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                                                                威廉希尔
                                                                2019年3月29日