大会特邀报告:


青年学者邀请报告:

  • 陈绍示(中国科学院数学与系统科学研究院)
    题目:D-finite functions: rationality and singularity analysis
    摘要:D-finite functions are solutions of systems of linear partial differential equations with polynomial coefficients of special type. This class of functions has been systematically investigated by R. Stanley in his book Enumerative Combinatorics (Volume II) as basic generating functions in combinatorics. In this talk, we will present some results related to the loindexcal and global studies of D-finite functions. Singularity analysis explores the local behavior of analytic functions. In the local aspect, we will study the apparent singularities of D-finite functions and the corresponding desingularization algorithms. In the global aspect, we prove that a multivariate D-finite power series with coefficients from a finite set is rational. This generalizes a rationality theorem of van der Poorten and Shparlinski in 1996. As an application, we will show how this result can be used to study the nonnegative integer points on algebraic varieties. This talk is based on my recent joint works with Jason P. Bell, Manuel Kauers, Ziming Li, Michael Singer and Yi Zhang.

    冯如勇(中国科学院数学与系统科学研究院)
    题目:Direct and inverse problems in difference Galois theory
    摘要:Difference Galois theory is a generalization of the usual Galois theory to linear difference equations.
    Direct and inverse problems are two fundamental problems in this theory. Direct problem asks how to calculate the Galois group of a given linear difference equation, and inverse problem concerns which groups appear as Galois groups of linear difference equations. In this talk, we will give a brief introduction to difference Galois theory and survey recent work on direct and inverse problems.

    雷娜(大连理工大学)
    题目:Automatic hexahedral mesh generation based on surface foliations
    摘要:
    For the purpose of isogeometric analysis, one of the most common ways is to construct structured hexahedral meshes, which have regular tensor product structure, and fit them by volumetric T-Splines. This theoretic work proposes a novel surface quadrilateral meshing method, colorable quad-mesh, which leads to the structured hexahedral mesh of the enclosed volume for high genus surfaces.
    The work proposes the following algorithm: the user first specifies a height parameter for each loop from an admisible curve system, which is a set of disjoint, simple loops automaticly computed on a high genus surface; a unique Strebel differential is computed with the combinatorial type and the heights prescribed by the user; the Strebel differential assigns a flat metric on the surface and decomposes the surface into cylinders; a quad-mesh is generated by splitting each cylinder into two quadrilaterals, followed by subdivision; the surface cylindrical decomposition is extended inward to produce a solid cylindrical decomposition of the volume; the hexahedral meshing is generated for each volumetric cylinder and then glued together to form a globally consistent hex-mesh.

    李新(中国科学技术大学)

    题目:AS++ T-splines and Iso-geometric Analysis: a perfect couple
    摘要:
    This talk will review the background of T-spline based isogeometric analysis. As the main motivation of construction design-through-analysis technology, we identify a new class of T-splines which have tighter relation with design and meanwhile maintain all the basic and good mathematical properties as B-splines and AS T-splines. We refer to them as AS++ T-splines, which prefectly couple with design and analysis.

    申立勇(中国科学院大学)
    题目:
    基于μ基的有理张量积曲面的隐式化
    摘要:μ基方法是曲线曲面隐式化的重要方法之一,但是基于μ基结式的曲面隐式化仍然不完善,例如μ基结式常常含有除隐式方程之外的多余因子。因此我们研究了使得结式无多余因子的μ基存在性,并定义此类μ基为强μ基。通过计算分析表明,大多数曲面并不含有强μ基。针对一般μ基,我们分析发现,μ基结式的多余因子只能来自与张量参数表示的部分基点或者参数无穷远点。进一步,我们鉴定出各种多余因子的类型并且给出了它们的计算方法,除去多余因子即可得到隐式方程。

    李冬梅(湖南科技大学)
    题目:
    Groebner bases and the equivalence of polynomial matrices
    摘要:
    We investigate the following conjecture and open problem:
    (1) A valuation ring R is 1-Groebner if and only if R is an archimedean ring;
    (2) Is a 1-Groebner valuation ring coherent?
    We firstly prove that a zero-dimensional valuation ring is 1-Groebner. Furthermore, we give a positive answer to (1) and a negative answer to (2).
    Finally, we present some new results on the equivalence of polynomial matrices.