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2017年青年数学论坛



会议时间:2017415-17

          414日全天报到,417日离会

会议地点:数学科学学院1518多媒体教室

 

住宿信息:合肥天鹅湖大酒店,合肥市政务新区东流路888号。

交通信息:415日早800在酒店门口上车集体前往科大东区数学学院;下午530在数学学院楼下集合上车,集体返回酒店。

 

会议报告

415 周六

830-840

开幕式

840-940

报告题目:

Harmonic mappings for bounded distortion shape deformation and interpolation

报告人:

陈仁杰  德国马克斯普朗克计算机研究所

报告摘要:

Harmonic mappings are extensively used in geometry processing applications to produce visually appealing deformations. We establish the sufficient and necessary conditions for a harmonic planar mapping to have bounded distortion. Our key observation is that these conditions relate solely to the boundary behavior of the mapping. This leads to an efficient and accurate algorithm that supports handle-based interactive shape-and-image deformation and is demonstrated to outperform other state-of-the-art methods. The particular structure of harmonic mappings further allows efficient shape interpolation. Given the closed-form expressions for the interpolants, our interpolation algorithm runs embarrassingly in parallel and is orders of magnitude faster than state-of-the-art methods due to its simplicity, yet it produces mappings that are superior to those existing techniques due to guaranteed bounds on geometric distortions.

950-1050

报告题目:

Weak approximation for 0-cycles on products of varieties

报告人:

梁永祺 巴黎七大

报告摘要:

We consider the sequence

 

 

QQ截图20170406084941.jpgfor smooth projective varieties over number fields. Its exactness is
conjectured by Colliot-Th′en`ene{Sansuc and Kato{Saito, it means roughly
that the Brauer{Manin obstruction is the only obstruction to weak approximation for 0-cycles.
We work on the compatibility of the exactness for products of varieties. Assume that (E) is exact for a rationally connected variety X
(after all finite extensions of the base field). One may ask the question :
For which family of varieties Y the sequence (E) is exact for X × Y ?
When Y is a smooth projective curve with the finiteness of the
Tate{Shafarevich group of its jacobian assumed, Harpaz and Wittenberg give a positive answer to the question (for much more general
fibrations rather than only for products). We will talk about the case
where Y is a smooth compactification of a homogeneous space.

1100-1200

报告题目:

The monodromy theorem for compact Kähler manifolds and smooth quasi-projective varieties

 

报告人:

刘永强 KU Leuven

 

报告摘要:

Given any connected topological space X, assume that there exists an epimorphism from the fundamental group of X to the free ableian group Z. The deck transformation group Z acts on the associated infinite cyclic cover of X, hence on the homology group of the covering space with complex coefficients. This action induces a linear automorphism on the torsion part of the homology group as a module over the complex Laurent polynomial ring, which is a finite dimensional complex vector space. We study the sizes of the Jordan blocks of this linear automorphism. When X is a compact K\"ahler manifold, we show that all the Jordan blocks are of size one. When X is a smooth complex quasi-projective variety, we give an upper bound on the sizes of the Jordan blocks, which is an analogue of the Monodromy Theorem for the local Milnor fibration.    This is a joint work with Nero Budur and Botong Wang.

1200-1400

Lunch & break

14:00-15:00

报告题目:

Boundary $C^{1,\alpha}$ regularity of Potential functions in Optimal transportation

报告人:

陈世炳  澳洲国立大学

报告摘要:

We provide a different proof for the global $C^{1,\alpha}$ regularity of potential functions in optimal transport problem, which was originally proved by Caffarelli. Moreover, our method applies to a more general class of domains. This is based on a joint work with Elina Andriyanova.

1510-1610

报告题目:

Scaling Limits of Critical Inhomogeneous Random Graphs

报告人:

Minmin Wang    Institut Henri-Poincaré and University of Bath

报告摘要:

Branching processes are known to be useful tools in the study of random graphs, in particular in understanding the appearance of a phase transition in the sizes of the largest clusters of the graphs. Recently, growing interests are paid to inhomogeneous random graphs. In this talk, we look at one particular model of such graphs, called the Poisson random graph, where edges are formed with probabilities proportional to some prescribes weights on the vertices. One challenge in the study of inhomogeneous random graphs is to describe the geometry of the graphs around the critical point. In the case of Poisson random graph, we obtain a simple representation of the graph using Galton-Watson trees (genealogy trees of branching processes). Relying on this representation and previous works of Duquesne & Le Gall on the convergence of Galton-Watson trees, we prove that in the critical window, the scaling limits of the largest components of the Poisson random graphs are a collection of almost-tree-like compact metric spaces, which can be constructed explicitly from the so-called Levy processes without replacement.
Based on a joint work with Nicolas Broutin and Thomas Duquesne.

1620-1720

报告题目:

Computing with functions

报告人:

Kuan Xu, University of Kent

报告摘要:

In very recent years, the idea of computing with functions has been sparkled by the endeavor of the Chebfun project. Polynomial approximations of functions enables functional operations and operators of all kinds to be numerically approximated using fast, accurate, and robust algorithms based on these approximations, giving people the feel of symbolic computing but with the lightning speed of numerical computation. The idea of computing with functions has also extended to the solution of differential and integral equations. In this talk, the core idea of computing with functions and the underlying mathematics of Chebfun project will be discussed with the aid of hands-on-keyboard demos.

1730-

Dinner

 

 

416 周日全天 会后讨论


 

 

 

主办单位:数学科学学院

          中国科学技术大学

  科大主页 | 国家数学与交叉科学中心(合肥) | 中科院吴文俊数学重点实验室 |
中科院数学与系统科学研究院 | 北京国际数学研究中心 | 安徽省数学会