来源:数学科学学院 发布时间:2021-07-06   16148

34. 5月第二周讲座

(1)A Periodic Discrete Model on Wolbachia Transmission Dynamics in Mosquito Populations


报告人:庾建设 教授(广州大学)


地点:腾讯会议ID:482 426 921

摘要:How to prevent and control mosquito-borne diseases, such as malaria, dengue fever and Zika, is still an urgent worldwide public health problem. The most conventional method for the control of these diseases is to directly kill mosquitoes by spraying insecticides or removing their breeding sites. However, the traditional method is not effective enough to keep the mosquito density below the epidemic risk threshold. With promising results internationally, the World Mosquito Program's Wolbachia method is helping to reduce the occurrence of diseases transmitted by mosquitoes. In this talk, I will introduce a periodic discrete model to study the dynamics of Wolbachia infection frequency in mosquito populations where infected mosquitoes are impulsively released. This model has three notable characteristics: first, it covers all relevant existing models since 1959 as special cases; second, it develops with the development of experiments and mosquito factories; and finally, it presents us with a number of unresolved problems. This is a joint work with Professors Jia Li and Bo Zheng.

报告人简介:庾建设,博士,教授,博士生导师,国家杰出基金获得者,国家有突出贡献的中青年专家,全国模范教师,国家“百千万人才工程”第一层次、第二层次人选,教育部跨世纪优秀人才,享受政府特殊津贴专家,广州大学应用数学研究中心主任。庾建设教授长期从事微分方程动力系统、差分方程及生物数学模型的理论与应用研究,先后主持国家自然科学基金项目10余项,其中重点项目3项,数学交叉研究平台项目2项;曾获国家级教学成果一等奖1项,省部级科技成果、教学成果一等奖多项。近十年来,致力于应用数学的理论研究及其在基因表达、蚊媒传染疾病防控等方面的应用,已在Nature、PLOS Computational Biology、J. Diff. Equas.、J. Dyna. Diff. Equas.、Siam J. Math. Anal.、SIAM J. Appl. Math.、Journal of Math. Biol.、J. Theo. Biol.、Math. Biosciences、Bull. Math. Biol.等重要数学、应用数学国际刊物发表论文多篇。


(2)Branching laws: from symmetric groups to p-adic general linear groups




地点:腾讯会议ID919 481 810

摘要:The branching law in representation theory studies the restriction of a group representation to a subgroup representation. This talk will take a tour on some developments on branching laws of some closely related type A algebras, starting from the classical branching law for symmetric groups, then going into affine Hecke algebras of type A, and ending with the modern development of the local non-tempered Gan-Gross-Prasad conjecture and its beyond. Our focus will be on connections between those branching laws.

报告人简介:陈佳源现任复旦大学上海数学中心青年研究员,曾入选国家海外高层次引进人才青年项目。2014年博士毕业于美国犹他大学。2015-2018年先后在荷兰阿姆斯特丹大学及美国乔治亚大学从事博士后研究。主要研究方向为表示论及朗兰兹纲领,近年工作主要围绕在分支法上的Gan-Gross-Prasad猜想。主要工作发表在Invent. Math., Duke Math. J., Crelle's Journal, Advances in Mathematics 等重要期刊上。


33. 5月第一周讲座

(1)Nilpotent orbits in modular representations of reductive Lie algebras and related topics




地点:腾讯会议ID:640 804 118(密码:2022)

摘要:In positive characteristic, representations of reductive Lie algebras are not understood very well. So far lots of basic problems have been neither solved nor understood. In this talk, I will introduce some advances in this fields. In particular, I will give an account of the role of nilpotent orbits therein, and introduce our recent works in the fields and related topics jointly with Y.Li, Y.Yao,Y.Zeng and so on, including:

(1) partial answers to our support variety conjecture.

(2) Partial answers to Friedlander-Parshall’s question.

(3) Centers of finite W-algebras and Azumaya property.

(4) Solutions of regular/subregular nilpotent irreducible modules and realizations for An with p | n+1 while  the solutions when p ∤ n+1 are due to Friedlander-Parshall (1988) and Jantzen (1999) respectively.

报告人简介:舒斌,华东师范大学数学科学学院教授,主要从事李(超)代数与代数(超)群的表示,以及代数群作用下幂零轨道及其相关联的有限W-代数等方面的研究。特别在素特征域李理论与表示论方面完成系列研究工作。 目前承担国家自然科学基金项目。


(2)One-point distribution of the geodesic in directed last passage percolation

One-point distribution of the geodesic in directed last passage percolation(5月5日10:00).pdf


地点:腾讯会议ID:141 238 776


(3)An approximation to steady state of M/Ph/M+n queue


报告人:徐礼虎 副教授(澳门大学)


地点:腾讯会议ID:582 863 420

摘要:In this paper, we develop a stochastic algorithm based on Euler-Maruyama scheme to approximate the invariant measure of the limiting multidimensional diffusion of the M/Ph/n+Mqueue. Specifically, we prove a non-asymptotic error bound between the invariant measures of the approximate model from the algorithm and the limiting diffusion of the queueing model. Our result also provides an approximation to the steady-state of the prelimit diffusion-scaled queueing processes in the Halfin-Whitt regime given the well established interchange of limits property. To establish the error bound, we employ the recently developed Stein's equation and Malliavian calculus for multi-dimensional diffusions. The main difficulty lies in the non--differentiability of the drift in the limiting diffusion, so that the standard approaches in Euler type of schemes for diffusions and Stein's method do not work. We first propose a mollified diffusion which has a sufficiently smooth drift to circumvent the nondifferentiability difficulty. We then provide some insights on the limiting diffusion and approximate diffusion from the algorithm by investigating some useful occupation times, as well as the associated Harnack inequalities, the support of the invariant measures and ergodicity properties. These results are used in analyzing the Stein's equation, which provide useful estimates to bound the differences between the corresponding invariant measures.

报告人简介:徐礼虎,澳门大学副教授,博士生导师。2001年毕业于山东大学,获学士学位;2004年毕业于北京大学,获硕士学位;2008年毕业于英国帝国理工学院,获博士学位。主要研究方向:随机分析、极限理论。在国内外学术刊物Annals of Statistics, Probability Theory and Related Fields, Bernoulli等上发表学术论文多篇。


(4)The Diagonal Reduction Algebra of the Lie Superalgebra osp(1|2)


报告人:Jonas T. HartwigIowa State University


地点:腾讯会议ID:985 173 823

摘要:Reduction algebras are known by many names in the literature, including step algebras, Mickelsson algebras, Zhelobenko algebras, and transvector algebras, to name a few. In this talk we present some results about the diagonal reduction superalgebra A of the orthosymplectic Lie superalgebra osp(1|2). We prove that the ghost center (center plus anti-center) of A is generated by two central elements and one anti-central element (analogous to the Scasimir due to Lesniewski). We also classify all finite-dimensional irreducible representations of A. As an application we provide an explicit decomposition of an infinite-dimensional tensor product of osp(1|2)-representations.

This talk is based on joint work with Dwight Anderson Williams II.

报告人简介:Dr. Jonas T. Hartwig is currently Associate Professor of Mathematics at Iowa State University. He received his Ph.D. in 2008 from Chalmers University of Technology. He has held postdoctoral research positions at Korteweg-de Vries Institute for Mathematics at University of Amsterdam and Institute of Mathematics and Statistics at University of São Paulo, and was a Visiting Assisant Professor at University of California Riverside. Dr. Hartwig's research interests include representation theory for Lie algebras, quantum groups and related algebras, and connections to geometry and mathematical physics.


(5)Counterexamples for chromatic and dichromatic number

Counterexamples for chromatic and dichromatic number(5月6日09:00).pdf


地点:ZOOM会议ID:843 0428 2616(密码:121323)


(6)Variable Screening for Several Varying Coefficient Models with Ultrahigh-Dimensional Survival Data



地点:腾讯会议ID:922 418 797


(7)Rainbow structures, Latin squares & graph decompositions


报告人:Prof. Benny Sudakov(ETH Zurich)


地点:ZOOM会议ID:271 534 5558(密码:YMSC)

摘要:A subgraph of an edge-coloured graph is called rainbow if all its edges have distinct colours. The study of rainbow subgraphs  has a long history in discrete mathematics, going back to the 18th century work of Euler on Latin squares. Since then rainbow structures were the focus of extensive research and found numerous applications in design theory and graph decompositions. Many problems in this area can be solved or partially solved by applying probabilistic arguments. In this talk we discuss a few such applications focusing on recent progress on some long-standing open questions.

报告人简介:Benny Sudakov received his PhD from Tel Aviv University in 1999. He had appointments in Princeton University, the Institute for Advanced Studies, Princeton and in UCLA.  Currently he is a professor of mathematics in ETH, Zurich. Sudakov is the recipient of an Alfred P. Sloan Fellowship, NSF CAREER Award and Humboldt Research Award. He is an AMS Fellow, member of Academia Europaea and was an invited speaker at the 2010 International Congress of Mathematicians. His main research interests are combinatorics and its applications to other areas of mathematics and computer science.


(8)Existence, Uniqueness and Stability of Bistable Waves for Monotone Semiflows


报告人:Xiaoqiang Zhao(Memorial University of Newfoundland, Canada


地点:腾讯会议ID:830 276 126

摘要:In this talk, I will first give a brief review on the existence of bistable traveling waves for monotone semiflows. Under appropriate assumptions, we then establish the abstract results on the uniqueness and stability of bistable waves for discrete and continuous-time evolution systems in a continuous habitat by appealing to a global convergence theorem for monotone semiflows. We also extend such a result to time-periodic semiflows, and apply the general theory to a class of reaction-diffusion-advection systems in a cylinder. 


32. 4月第四周讲座


报告人:谈之奕 教授(浙江大学)


地点:腾讯会议ID:577 536 421



(2)On Construction of Optimal Exact Confidence Intervals

报告人:Weizhen Wang(Wright State University)


地点:腾讯会议ID:693 857 421

摘要:A general method, named the h-function method, is introduced to unify the constructions of level-α exact test and 1-α exact confidence interval. Using this method, any given confidence interval can be improved as follows: (i) an approximate interval, including a point estimator, is modified to an exact interval; (ii) an exact interval is refined to be an interval that is a subset of the previous one; (iii) two intervals, each utilizing partial data, are combined to form an exact interval that utilizes the complete data. Some real datasets, including Johnson & Johnson's Janssen vaccine (2021), are used to illustrate the method.

报告人介绍:Weizhen Wang received his B.S. and M.S. at Peking University in 1987 and 1990, respectively, and completed his Ph.D. in Statistics at Cornell University in 1995. After one-year visit at Purdue University, he joined Wright State University, and has been a Professor of Statistics since 2007. His research includes bioequivalence, exact parametric and nonparametric inferences, saturated and adaptive designs, categorical data analysis, foundation of statistics, statistical computation, and clinical trial. His current primary interest is exact statistical inference and the implementation in R.





地点:腾讯会议ID:354 444 305


(4)Minimax rates for sparse signal detection under correlation



地点:腾讯会议ID:417 340 765(密码:13579)


31. 4月第三周讲座

(1)Multi-bubble Bourgain-Wang solutions to mass-critical (stochastic) nonlinear Schrödinger equations


地点:腾讯会议ID:575 879 691


摘要:In this talk, we are concerned with a general class of focusing mass-critical nonlinear Schrödinger equations (NLS) with lower order perturbations, for which the pseudoconformal symmetry and the conservation law of energy can be absent. Two canonical examples are the stochastic NLS driven by the linear multiplicative noise and the deterministic NLS. In dimensions one and two, we construct Bourgain-Wang type blow-up solutions, concentrating at finitely many distinct singularities, and prove that they are unique if the asymptotical behavior is within the order for (T-t)^{4+}, t close to the blow-up time T. Moreover, through the pseudo-conformal transform, this also provides examples of non-pure multi-solitons (with dispersive term) to mass-critical deterministic NLS. The talk is based on the work in joint with Michael Röckner and Yiming Su.


(2)A Polynomial Algorithm for Best Subset Selection



地点:腾讯会议ID:935 419 590


(3)Torelli-type theorems for gravitational instantons





30. 4月第二周讲座

(1)Mixture proportional hazards cure model with latent variables



地点:腾讯会议ID:370 609 288


(2)On the anti-canonical geometry of weak Q-Fano 3-folds, III


On the anti-canonical geometry of weak Q-Fano 3-folds, III(4月13日15:00-16:00).pdf


地点:腾讯会议ID:839 603 441(密码:535575)


(3)On the compressible Navier-Stokes equations in the whole space: well-posedness, stability and asymptotic analysis


On the compressible Navier-Stokes equations in the whole space: well-posedness, stability and asymptotic analysis(4月15日10:00-11:00).pdf


地点:腾讯会议ID:643 286 692


(4)Asymptotics of Multiscale Stochastic Systems



地点:腾讯会议ID:160 680 061





地点:腾讯会议ID:160 680 061



29. 4月第一周讲座

(1)The sharp estimates of functions and the related rigidity, stability

【中国科学技术大学数学科学学院Spectral Geometry Seminar系列讲座之009】


地点:腾讯会议ID:981 472 543(密码:202204)

报告人:Guoyi XU(Tsinghua University)

摘要:Since Cheng-Yau proved the gradient estimate of harmonic functions in 1975, their method played important role in geometric analysis. Its philosophy was generalized to prove the lower bound of eigenvalues and parabolic Harnack estimate by Li-Yau. In this talk, we will discuss the sharp gradient estimate for harmonic functions, sharp Dirichlet eigenvalues in geodesic ball. Furthermore, we present the corresponding sharp estimate for Green's function and heat kernel, and the rigidity and stability of those estimates will also be discussed. This is a survey report based on my former work and the joint work with Haibin Wang---Jie Zhou, and Qixuan Hu----Chengjie Yu. Only basic Riemannian geometry and PDE knowledge is enough to understand most part of the talk.





地点:腾讯会议ID:855 435 497(密码:220406)


(3)On Functional Processes with Multiple Discontinuities



地点:腾讯会议ID:910 310 323

报告人:Li Jialiang( National University of Singapore )

摘要:We consider the problem of estimating multiple change points for a functional data process. There are numerous examples in science and finance in which the process of interest may be subject to some sudden changes in the mean. The process data that are not in a close vicinity of any change point can be analysed by the usual nonparametric smoothing methods. However, the data close to change points and contain the most pertinent information of structural breaks need to be handledwith special care. This paper considers a half-kernel approach that addresses the inference of the total number, locations and jump sizes of the changes. Convergence rates and asymptotic distributional results for the proposed procedures are thoroughly investigated. Simulations are conducted to examine the performance of the approach, and a number of real data sets are analysed to provide an illustration.

报告人简介:栗家量,新加坡国立大学统计与应用概率系教授,同时在杜克大学-新加坡国大医学院与新加坡眼科研究所任兼职教授。栗教授于2001年中国科学技术大学获得统计学学士学位,分别于2005年和2006年在美国威斯康星大学麦迪逊分校获得公共健康学硕士学位和统计学博士学位。现在研究兴趣包括工具变量、子集分析、变点模型、结构方程、精准医学、诊断医学、 模型平均、非参、生存分析等。已发表论文160余篇,他是ASA的Fellow和ISI的Elected Member。


(4)Optimal estimation of Gaussian mixtures via denoised method of moments



地点:腾讯会议ID:404 723 919


28. 3月第五周讲座

(1)Learning deep generative models and its applications

Learning deep generative models and its applications(3月29日14:30).pdf


地点:腾讯会议ID:433 373 606(密码:200433)


(2)Asymptotic for the Cubic Moment of Maass Form L-Functions


地点:腾讯会议ID:839 225 752(密码:618034)


摘要:In this talk, I will talk about the cubic moment of central L-values for Maass forms. It was studied by Aleksandar Ivić at the beginning of this century, obtaining asymptotic on the long interval [0, T] with error term O(T8/7+ε) and Lindelöf-on-average bound on the short window [T-M, T+M] for M as small as Tε. Ivić’s results are improved in my recent work; in particular, Ivić’s conjectured error term O(T1+ε) is proven. Our proof follows the standard Kuznetsov–Voronoi approach stemed from the work of Conrey and Iwaniec. Our main new idea is a combination of the methods of Xiaoqing Li and Young.


(3)Characters of non-integral weight modules of exceptional Lie superalgebras


地点:腾讯会议ID:820 916 050

报告人:罗栗 教授(华东师范大学)

摘要:In this talk, we shall give a brief introduction about character formulas of Lie superalgebras. We shall also show our recent developments on the characters of non-integral weight modules of exceptional Lie superalgebras D(2|1,zeta) and G(3). This is joint work with Chih-Whi Chen and Shun-Jen Cheng.


27. 3月第四周讲座

(1)Howe duality for exceptional theta correspondences

Howe duality for exceptional theta correspondences(3月22日10:00).pdf


地点:ZOOM会议ID:997 7952 4352(密码:SCMS)


(2)Machine Learning Approach to Mean Reversion Trading



地点:ZOOM会议ID:878 7426 3432(密码:150522)

报告人:Tim Leung (University of Washington)

摘要:We discuss a practical machine learning approach to construct portfolios with mean-reverting price dynamics. Our objectives are threefold: (1) design a portfolio that is well-represented by a mean-reverting process with parameters estimated by maximum likelihood, (2) select portfolios with desirable characteristics, such as high mean reversion, and (3) build a parsimonious portfolio, i.e. find a small subset from a larger collection of assets for long/short positions. Our data-driven method combines statistical learning and optimization. We present a specialized projected gradient algorithm to solve the constrained non-convex problem embedded in the trading problem. Numerical examples using empirical price data are provided.

报告人简介:Tim Leung is the Boeing Endowed Chair Professor in the Department of Applied Mathematics and the Director of the Computational Finance & Risk Management (CFRM) program and Quantitative Analytics Lab at University of Washington in Seattle. He has previously taught in the Department of Applied Mathematics & Statistics at Johns Hopkins University and in the Department of Industrial Engineering & Operations Research at Columbia University. He obtained his BS from Cornell University and PhD from Princeton University. His research in Quantitative Finance has been funded by the National Science Foundation (NSF). He has published over 70 peer-reviewed articles and several books on the topics of Mean Reversion Trading, ETFs, and more. Professor Leung is on the advisory board of the AI for Finance Institute and the editorial board of multiple journals. He has served as the Chair for the INFORMS Finance Section as well as the Vice Chair for the SIAM Activity Group on Financial Mathematics & Engineering.


(3)Gaussian Differential Privacy and the Edgeworth Accountant


地点:腾讯会议ID:943 727 127

报告人:Weijie Su(University of Pennsylvania)

摘要:Privacy-preserving data analysis has been put on a firm mathematical foundation since the introduction of differential privacy (DP) in 2006. This privacy definition, however, has some well-known weaknesses: notably, it does not tightly handle composition. In this talk, we propose a relaxation of DP that we term f-DP, which has a number of appealing properties and avoids some of the difficulties associated with prior relaxations. This relaxation allows for lossless reasoning about composition and post-processing, and notably, a direct way to analyze privacy amplification by subsampling. We define a canonical single-parameter family of definitions within our class that is termed Gaussian Differential Privacy, based on hypothesis testing of two shifted normal distributions. We prove that this family is focal to f-DP by introducing a central limit theorem, which shows that the privacy guarantees of any hypothesis-testing based definition of privacy converge to Gaussian differential privacy in the limit under composition. From a non-asymptotic standpoint, we introduce the Edgeworth Accountant, an analytical approach to compose f-DP guarantees of private algorithms. Finally, we demonstrate the use of the tools we develop by giving an improved analysis of the privacy guarantees of noisy stochastic gradient descent.

报告人简介:Weijie Su is an Assistant Professor in the Wharton Statistics and Data Science Department and, by courtesy, in the Department of Computer and Information Science, at the University of Pennsylvania. He is a co-director of Penn Research in Machine Learning. Prior to joining Penn, he received his Ph.D. in statistics from Stanford University in 2016 and his bachelor’s degree in mathematics from Peking University in 2011. His research interests span multiple testing, privacy-preserving data analysis, optimization, high-dimensional statistics, and deep learning theory. He is a recipient of the Stanford Theodore W. Anderson Dissertation Award in Theoretical Statistics in 2016, an NSF CAREER Award in 2019, an Alfred Sloan Research Fellowship in 2020, and the Society for Industrial and Applied Mathematics (SIAM) Early Career Prize in Data Science in 2022.



(4)Low regularity ill-poserdness for 3D elastic waves and for 3D ideal compressible MHD driven by shock formation



地点:ZOOM会议ID:995 3448 9420(密码:202203)


26. 3月第三周讲座




地点:腾讯会议ID:318 942 296


(2)Quantile Regression for Nonignorable Missing Data with its Application of Analyzing Electronic Medical Records


地点:腾讯会议ID:385 241 644


(3)Distinct distances on hyperbolic surfaces


报告人:Xianchang Meng(Shandong University)


地点:腾讯会议ID:861 8661 7196(密码:123555)

摘要:Erdős (1946) proposed the question of finding the minimal number of  distinct distances among any N points in the plane. Guth-Katz (2015) gave almost sharp answer for this question using incidence geometry and polynomial  partitioning. We consider this problem in hyperbolic surfaces associated with cofinite Fuchsian groups, i.e. the volume of the surface is finite. We prove a lower bound of the same strength as Guth-Katz. In particular, for any finite index subgroup of the modular group, we extract out the dependence of the implied  constant on the index.


25. 3月第二周讲座

(1)Density Interpolation Methods for Boundary Integral Equations



地点:ZOOM会议ID:985 2901 3634(密码:842307)




地点:腾讯会议ID:200 103 446





地点:腾讯会议ID:462 550 436



(4)Hodge-GUE correspondence

报告人:Di Yang(中国科学技术大学)


地点:腾讯会议ID:462 550 436

摘要:The Hodge–GUE correspondence describes an explicit relationship between certain cubic Hodge integrals on the Deligne–Mumford  moduli space of stable algebraic curves and connected GUE correlators of even valencies. In this talk, we describe this correspondence and its proof, and discuss its applications.  The talk is based on a series of joint work with Boris Dubrovin, Si-Qi Liu and Youjin Zhang.



24. 3月第一周讲座

(1)Nonparametric Identification and Estimation of the generalized additive model


地点:腾讯会议ID:473 398 863


(2)Robust Differential Abundance Test in Compositional Data



地点:腾讯会议ID:569 229 249


(3)Rogue Waves for Vector NLS Equation: Explicit Formula, Peak Amplitude and Large Parameter Asymptotic



地点:腾讯会议ID:334 114 179

摘要:In this talk, I will report the joint work with Liming Ling and Zhenya Yan on the study of rogue waves for vector NLS equation. Firstly, the background of rogue wave and some remarkable results will be recalled. Then I will give the explicit formulas ofrogue wave and high-order rogue wave solutions. Lastly, the structure characteristics of rogue waves will be reported including two kinds of peak amplitudes and large-parameter asymptotic.





地点:腾讯会议ID:160 892 833



23. Activation discovery with FDR control: Application to fMRI data



地点:腾讯会议ID:615 465 700


22. 12月第三周讲座

(1)On analogues of modular units for the moduli stack of Drinfeld shtukas



地点:ZOOM会议ID:970 2662 9834(密码:499643)



(2)The Neyman-Pearson lemma for convex expectations


报告人:Shaolin Ji(Shandong University)

嵇少林,现为山东大学金融研究院教授、博士生导师,师从彭实戈院士。1999年至今在山东大学工作。研究领域为金融数学、金融经济学、随机优化和非线性期望理论。近年来,嵇少林在《Review of financial studies》, 《Operations research》,《Probability theory and the related fields》和《SIAM Control and Optimization》等杂志上发表了一系列的成果。对金融市场中的学习理论、资本资产定价、随机优化问题和非线性期望理论进行了系统的研究。


地点:腾讯会议ID:347 351 716(密码:123456)


摘要:We study the Neyman-Pearson theory for convex expectations or equivalent convex risk measures on L^{∞}(μ). Without assuming that the level sets of penalty functions are weakly compact, a fixed representative pair (P^{∗},Q^{∗}) is found by a new method different from the convex duality method. Then we show that the optimal tests are just the classical Neyman-Pearson tests between the representative probabilities P^{∗} and Q^{∗}. Finally, we apply our results to a shortfall risk minimizing problem in an incomplete financial market.  (With Chuanfeng Sun).


21. 12月第二周讲座

(1)Collapsing Geometry of Hyperkaehler Four-Manifolds

报告人:Ruobing Zhang(Princeton University)

Ruobing Zhang is currently an assistant professor at Princeton University. He obtained his Ph.D. at Princeton University in 2016 under the supervision of Alice Chang and Paul Yang. His research focuses on differential geometry and geometric analysis.


地点:ZOOM会议ID:841 8772 1220(密码:430726)


摘要:This talk focuses on the recent resolution of the following three well-known conjectures in the study of Ricci-flat four manifolds (joint with Song Sun).

(1) Any volume collapsed limit of unit-diameter hyperkaehler metrics on the K3 manifold is isometric to one of the following: the quotient of a flat 3D torus by an involution, a singular special Kaehler metric on the topological 2-sphere, or the unit interval.

(2) Any complete non-compact hyperkaehler 4-manifold with quadratically integrable curvature, namely gravitational instanton, must have one of the following asymptotic model geometries: ALE, ALF, ALG, ALH, ALG* and ALH*.

(3) Any gravitational instanton can be compactified to an open dense subset of certain compact algebraic surface.

With the above classification results, we obtain a rather complete picture of the collapsing geometry of hyperkaehler four manifolds, i.e., classifications of Gromov-Hausdorff limit geometries, tangent cones, singularity formations, as well as all the rescaling bubbles.


(2)A spectral accurate solver for the elastic scattering problems based on spherical harmonics


赖俊,南京大学数学系本科,美国密西根州立大学应用数学博士毕业,曾任纽约大学柯朗数学研究所博士后及讲师,目前任浙江大学数学科学学院“百人计划”研究员,主要研究声波,电磁波及弹性波方程的散射与反散射问题,在数学知名杂志ACHA,SISC,Math Comp,Inverse Problems等发表文章多篇,主持国家面上项目一项,并参与基金委重大研究计划,基金委创新群体等研究,曾入选中组部高层次青年人才计划,获十一届全国反问题年会“优秀青年学术奖”。


地点:腾讯会议ID:921 659 018(密码:1234)


摘要:The scattering problems for elastic waves have recently received ever increasing attention in both the engineering and mathematical communities for their important applications in geophysics and seismology. In this talk we mainly discuss a spectral accurate solver for elastic scattering problems in three dimensions. In particular, we formulate the elastic problem by boundary integral equations. Through the Helmholtz decomposition, we split the elastic wave field into the compressional wave and shear wave. We apply the rotated vector spherical harmonics as the basis to discretize the coupled boundary integral equation. The well-posedness of the coupled system, as well as its applications to the multi-particle elastic scattering will also be discussed.


20. 12月第一周讲座

(1)A snapshot of serrano's conjecture

报告人:刘海东(中山大学,Sun Yat-sen University)


地点:腾讯会议ID:790 778 401(密码:428474)

摘要:Strictly nef divisors sit between nef divisors and ample divisors. A natural question is how far are strictly nef divisors from being ample. In this area, Serrano's conjecture predicts that after twisting by the canonical divisor a little bit, the adjoint strictly nef divisor should be ample. In this talk, I will survey some recent progress on this conjecture. (Part of my works is jointed with Roberto Svaldi, part is jointed with Shin-ichi Matsumura.)


(2)Least squares model averaging and its extensions



地点:腾讯会议ID:307 424 966


(3)Spatial signs and ranks based high-dimensional change point detection via random integration

报告人:张伟平 教授(中国科学技术大学)


地点:腾讯会议ID:556 2454 9135

摘要:Detecting change points is an important task in time series analysis to identify an abrupt and significant change in the data generating process. Most of the existing methods for change point detection are based on Hotelling's T2 type statistics, which are unreliable in high-dimensional situations due to the requirement for the consistent estimation of the covariance matrix. This paper proposed a novel nonparametric method to overcome this issue by using spatial signs and ranks random integration idea, which is tailored to high-dimensional change point detection problems. This random integration-based method is a unified framework that includes and extends many existing methods and can effectively handle high-dimensional non-normal data. In addition, we developed a generalized computationally efficient algorithm to calculate the rejection thresholds and an effective post-signal diagnostic procedure to identify the potential directions. Finally, numerical studies together with real data examples demonstrated that the proposed method can identify the change point efficiently.


19. 11月第四周讲座

(1)Softplus INGARCH Model



地点:腾讯会议ID:788 902 078


(2)On efficient dimension reduction with respect to the interaction between two response variables

报告人:骆威,2014年毕业于美国宾夕法尼亚州立大学,之后任职于美国Baruch College,于2018年加入浙江大学。骆威的研究方向包括充分降维和因果推断,在Annals of Statistics, Biometrika, JRSSB等统计国际学术期刊上发表(含接收)了多篇论文。


地点:腾讯会议ID:925 141 454https://meeting.tencent.com/dm/i2FXK5QrLwgz

摘要:In this talk, we propose the novel theory and methodologies for dimension reduction with respect to the interaction between two response variables, which is a new research problem that has wide applications in missing data analysis, causal inference, and graphical models, etc. We formulate the parameters of interest to be the locally and the globally efficient dimension reduction subspaces, and justify the generality of the corresponding low-dimensional assumption. We then construct estimating equations that characterize these parameters, using which we develop a generic family of consistent, model-free, and easily implementable dimension reduction methods called the dual inverse regression methods. We also build the theory regarding the existence of the globally efficient dimension reduction subspace, and provide a handy way to check this in practice. The proposed work differs fundamentally from the literature of sufficient dimension reduction in terms of the research interest, the assumption adopted, the estimation methods, and the corresponding applications, and it potentially creates a new paradigm of dimension reduction research. Its usefulness is illustrated by simulation studies and a real data example at the end.


(3)Quantile difference estimation with censoring indicators missing at random





18. 11月第三周讲座




地点:腾讯会议ID:623 287 888(密码:310027)


(2)Sample-wise Combined Missing Effect Models with Penalization



地点:腾讯会议ID:559 530 381


17. 概率统计学术报告(20211111)

题目:Credit Risk Propagation in Structural-Form Models





16. Geometric inequalities inspired by algebraic geometry

报告人:Jian Xiao(Tsinghua University)


地点:腾讯会议ID:184 722 527(密码:825882)

摘要:Geometric inequalities reveal relation between different geometric invariants, such as volume, surface area, width, diameter, etc. By the correspondences between convexity and positivity, such as mixed volumes of convex bodies and intersection numbers of divisors, we present a series of new geometric inequalities inspired by positivity results in algebraic and analytic geometry.


15. 浙江大学概率统计学术报告

(1)Auto-reservoir neural network for multistep-ahead prediction







地点:腾讯会议ID:657 471 697(线上)


14. 海量数据驱动场景及其数据科学方法

报告人:李丰 副教授(中央财经大学)


地点:Online(Tecent Meeting)

腾讯会议ID:804 4124 3260

摘要: 随着海量数据的涌现,全新的商业管理和决策场景依赖灵活高效的数据科学方法。只有熟练运用针对复杂数据的数据科学工具,才以满足海量实时数据快速响应需求。特别的,在分布式存储和计算的新常态下,依赖分布式平台上的实时数据科学方法可以提供最佳商业决策。这对人才能力有了前所未有的挑战。如何快速在数据浪潮中迅速学习并自我提升将会成为将来的关键。本报告通过介绍海量数据驱动场景及其数据科学方法,为将来志在数据驱动的新兴领域的同学知识储备和能力提升提供一些启发。

报告人信息:李丰博士现任中央财经大学统计与数学学院副院长、副教授。博士毕业于瑞典斯德哥尔摩大学,研究领域包括贝叶斯统计学,预测方法,大数据分布式学习等。曾获瑞典皇家统计学会Cramér奖,主持和参与多项国家自然科学基金项目。李丰博士最新研究成果发表在统计期刊Journal of Computational and Graphical Statistics,Journal of Business and Economic Statistics,经济与管理学期刊International Journal of Forecasting等,同时著有Bayesian Modeling of Conditional Densities,《大数据分布式计算与案例》和《统计计算》。李丰博士在世界贝叶斯大会,国际预测大会等作过邀请报告。


13. The inverse Gauss curvature flow and Orlicz Minkiwski problem

报告人:赵培标 教授(南京理工大学)


地点:Online(Tecent Meeting)

腾讯会议ID:284 297 954

摘要:In this note, we investigate a inverse gauss curvature flow, and obtain the long-time existence and convergence of this flow. As an application, we derive the existence of non-even smooth solution to the Orlicz-Minkowski problem.


12. Identification and estimation of nonignorable missing outcome mean without identifying the full data distribution



地点:Online(Tecent Meeting)

腾讯会议ID:979 3153 9451

摘要:We consider the problem of making inference about the population outcome mean of an outcome variable subject to nonignorable missingness. By leveraging a so-called shadow variable for the outcome, we propose a novel condition that ensures nonparametric identification of the outcome mean, although the full data distribution is not identified. The identifying condition requires the existence of a function as a solution to a representer equation that connects the shadow variable to the outcome mean. Under this condition, we use sieves to nonparametrically solve the representer equation and propose an estimator which avoids modeling the propensity score or the outcome regression. We establish the asymptotic properties of the proposed estimator. We also show that the estimator is locally efficient and attains the semiparametric efficiency bound for the shadow variable model under certain regularity conditions. We illustrate the proposed approach via simulations and a real data application on home pricing. The paper is available at http://arxiv.org/abs/2110.05776.

报告人信息:李伟,中国人民大学统计学院,生物统计与流行病学系讲师,北京大学数学科学学院博士。主要研究领域为因果推断、缺失数据、高维统计等。目前已在包括Biometrika, Journal of Econometrics, Biometrics等国际著名统计期刊上发表多篇学术论文。主持一项国家自然科学青年基金项目,参与完成多项国家自然科学基金面上项目。


11. Distinguished Colloquium——Orbit Method: From Matrices to Unitary Representations

报告人:Chen-Bo Zhu (National University of Singapore)


地点:Online(Zoom Meeting)

Zoom ID:819-3008-5234(密码:983788)


摘要:The talk is intended as a leisurely introduction to one of the fundamental tasks of representation theory: the construction of irreducible unitary representations. I will first discuss two major sources of unitary representations of Lie groups, one from Symplectic Geometry (Kirillov theory) and another from Number Theory (Langlands philosophy).  I will then introduce a constructive method called theta lifting which has been fruitful for representations of classical groups and discuss some recent applications of this method to unitary representation theory.

报告人信息:Chen-Bo Zhu is a professor of mathematics at the National University of Singapore (NUS), having first joined NUS in 1991. He received his BSc from Zhejiang University, China in 1984, and his PhD from Yale University, USA in 1990. His research interests are in representation theory of Lie groups. Together with his collaborators, he has contributed to the branching problem of smooth representations, the theory of local theta correspondence, and recently his focus has been on unitary representation theory. He is a fellow of the Singapore National Academy of Science.


10. Period Relations of Standard L-functions of Symplectic Type

报告人:田昉旸 博士(浙江大学数学科学学院)



摘要:A classical result of Euler says that the value of the Riemann-Zeta function at a positive even integer $2k$ is a rational multiple of $\pi^{2k}$. In the 1970s, a successive pioneering work of G. Shimura revealed the relation of different critical values of $L$-function that are attached to modular forms of $\mathrm{GL}_2$. This type of result, conjectured by D. Blasius for general linear groups, is called period relation of a certain automorphic $L$-function, which is closely related to a celebrated conjecture of P. Deligne.
    In this talk, I will discuss my work joint with Dihua Jiang and Binyong Sun on the period relation for the twisted standard L-function $L(s, \Pi\otimes\chi)$, where $\Pi$ is an irreducible cuspidal automorphic representation of $GL_{2n}(\mathbb{A})$ which is regular algebraic and of symplectic type.  Along this talk, I will also discuss the key ingredient of this project - the existence of uniform cohomological test vector, which provides the most precise information on the archimedean local integrals.


9. Asymptotics for the matrix-valued Keller-Rubinstein-Sternberg problem

报告人:王伟 研究员(浙江大学)



腾讯会议ID:116 386 443(密码:0915)

报告摘要:We will talk about the asymptotical behaviour of a matrix-valued Allen-Cahn equation when a small parameter tends to zero. Precisely, we show that the limit system is a two-phases flow system: the phase interface evolves according to the mean curvature flow; in two bulk phase regions, the solution obeys the harmonic map heat flow into two different manifolds; on the interface, the phase matrices in two sides satisfy a novel mixed boundary condition.

The proof follows the roadmap developed by de Mottoni-Schatzman and Alikakos-Bates-Chen: we first construct an approximate solution solving the regularized system up to arbitrary small terms, and then we prove a spectral lower bound for the linearized operator around it, and finally we estimate the difference between the true solution and the approximate solution. The main difficulties come from the inherent (partially minimal pairing) property of this problem.

This is joint work with Mingwen Fei, Fanghua Lin and Zhifei Zhang.


8. Social Proximity and Bank Lending




腾讯会议ID:112 930 838(密码:200433)

报告摘要:Using a proprietary data set, we explore the role of social proximity in bank lending. We uncover evidence of a significant social proximity effect on private information acquisition. Local loan officers have better information to identify higher-quality borrowers through improved screening. This advantage is greater when firms have higher information asymmetry and lower ratings. Results suggest that sociocultural resources drive locals' informational advantages and improve their lending performance.


7. Nesterov加速与高精度微分方程




腾讯会议ID:242 107 980




6. The Unconditional Uniqueness for the Energy-critical and Supercritical NLS

报告人:陈旭文(Department of Mathematics, University of Rochester)

时间:7月12日 10:00-11:00



报告摘要:We prove the unconditional uniqueness for the R^d/T^d cubic/quintic energy-critical and supercritical NLS.


5. 吴文俊数学重点实验室组合图论系列讲座3

题目:Basis-finding algorithm for decoding fountain codes for DNA storage

报告人:Xuan He, Southwest Jiaotong University, China

时间:7月10日 16:30-17:30

地点:Online(Tecent Voov meeting)

腾讯会议ID:630 503 561


报告摘要:Due to its extremely high storage density, longevity, and low maintaining cost, DNA storage becomes a promising candidate for archiving massive data in the future. Up to now, the DNA fountain scheme achieves the highest net information density (1.57bits/nt). However, it adopts a decoding algorithm for fountain codes, which can only work for correct received symbols and is thus not efficient enough for the DNA storage scenario where some received symbols may have undetected errors. This motivates us to propose a basis-finding algorithm (BFA). The BFA is the only known efficient hard-decision decoding algorithm for fountain codes for the general scenario where there exist some erroneous received symbols. This report gives a brief review of the DNA storage, DNA fountain scheme, and BFA.


4. 吴文俊数学重点实验室组合图论系列讲座2

题目:Improved Coding over Sets for DNA-Based Data Storage

报告人:Hengjia Wei, Ben-Gurion University, Israel

时间:7月10日 15:30-16:30

地点:Online(Tecent Voov meeting)

腾讯会议ID:630 503 561


报告摘要:In this talk, we look at error-correcting codes over sets, which have applications to DNA-based data storage. The DNA-storage channel receives a set of sequences, and produces a corrupted version of the set, including sequence loss, symbol substitution, and symbol insertion/deletion. We study two parameter regimes. New bounds on code parameters are provided, which improve upon known bounds. New codes are constructed, at times matching the bounds up to lower-order terms or small constant factors.


3. 吴文俊数学重点实验室组合图论系列讲座1

题目:Non-overlapping codes

报告人:Qi Wang, Southern University of Science and Technology, China

时间:7月10日 14:30-15:30

地点:Online(Tecent Voov meeting)

腾讯会议ID:630 503 561


报告摘要:Non-overlapping codes have been investigated for decades, and have recently found important applications in DNA storage systems. In this talk, I will first survey important results on non-overlapping codes, and then talk about some recent new results.


2. Profinite completion and surface mapping classes

报告人:Yi Liu (Beijing International Center for Mathematical Research, Peking University)

时间:6月24日 15:00-16:30

地点:Lecture Hall, Institute for Advanced Study in Mathematics, No.7 teaching building


1. 数学及其交叉学科前沿论坛第一期



时间:6月18日 14:00-16:00



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