### 中俄数学中心——吉大论坛（Sino-Russian Mathematics Center-JLU Colloquium）

Speaker：Vladimir Salnikov (CNRS / La Rochelle University)

Time：2022年12月1日 15:30-16:30

https://us02web.zoom.us/j/8620620549?pwd=bGhsaG15WjRza2V3ZEN4TzJYZ1FZQT09

Abstract：In this talk I introduce some natural constructions from the "graded world", paying particular attention to the differences between N- and Z- graded manifolds. I will start by the construction of the sheaf of functions on graded manifolds and describe its structure. The intrinsic properties of this functional space are conveniently given using the language of filtrations, allowing to formulate the analog of Batchelor’s theorem. Afterwards I will briefly introduce graded Hopf algebras and Harish-Chandra pairs, which in turn provide the result of equivalence of categories between graded Lie groups and algebras. These constructions are then used to solve the integration problem of differential graded Lie algebras to differential graded Lie groups. Time permitting, I will also say a few words on canonical forms of differential graded manifolds.

BioVladimir Salnikov is a researcher at CNRS (National Centre for Scientific Research), La Rochelle University, France. His scientific interests are graded and generalized geometry, dynamical systems, applications to mechanics and theoretical physics.

Racks, Leibniz algebras and rack bialgebras

Speaker：Friedrich Wagemann (University of Nantes)

Time：2022年11月29日-12月2日

Abstract：Groups, Lie algebras and associative bialgebras are linked by various functors which are important in Lie theory. We argue that this triad may be generalized to Racks, Leibniz algebras, rack bialgebras, which enjoy roughly the same links. In this minicourse, we will mainly discuss the cohomology of these structures.

 Date of Lecture Name (Title) of Lecture Beijing Time November29, 2022 Groups,Lie algebras and associative bialgebras 20:00-21:00 November29, 2022 Racks, Leibniz algebras and rack bialgebras 21:00-22:00 November30, 2022 Cohomology of Racks 20:00-21:00 November30, 2022 Periodicity in algebraic K-theory 21:00-22:00 December1, 2022 Cohomology of Leibniz algebras 20:00-21:00 December1, 2022 Cohomology of nilpotent Leibniz algebras 21:00-22:00 December2, 2022 Deformation cohomology of rack bialgebras 20:00-21:00 December2, 2022 Deformation cohomology of rack bialgebras vs cohomology of Leibniz algebras 21:00-22:00

BioFriedrich Wagemann, is a Professor from University of Nantes, France. He mainly studies Lie Theory and Mathematical Physics. He has published more than 40 high-level academic papers in Comm. Math. Phys., Adv. Math., Trans. Amer. Math, Soc., Pro. Lond. Math. Soc., IMRN and other journals.

Quasi-local mass and geometry of scalar curvature

Speaker：Yuguang Shi (Peking Universtiy)

Time：2022年11月25日  10:30-11:30

Meeting ID：腾讯会议：520-112-012

Abstract：Let (Σ^(n-1),γ) be an (n-1)-dimensional orientable Riemannian manifold, H be a positive function on Σ^(n-1), Gromov’s asked under what conditions γ is induced by a Riemannian metric g with nonnegative scalar curvature, for example, defined on Ω^n, and   H is the mean curvature of Σ in (Ω^n,g) with respect to the outward unit normal vector? By the recent result due to P. Miao we know such H cannot be too large, so the next natural question is what is “optimal” H so that such a fill-in for the triple (Σ^(n-1),γ,H) exits? It turns out that the problem has deep relation with positive mass theorem, in this talk I will talk about some known results relate to this topic. My talk is based on my joint works with Dr. Wang Wenlong, Dr.Wei Guodong，Dr. Zhu Jintian, Dr.Liu Peng, Dr. Hu Yuhao.

Bio：史宇光，1996年在中科院数学研究所获博士学位，1997年至1999年分别于香港中文大学，北京大学数学科学学院从事博士后研究，后留北大工作。曾获得国家杰出青年基金项目资助，当选长江特聘教授，入选第二批国家“万人计划”科技创新领军人才。于2010年，获第十一届中国青年科技奖；2011年，获理论物理国际中心（ICTP）Ramanujan奖；2020年，获教育部高等学校科学研究自然科学奖一等奖。

Local derivations and automorphisms on solvable Lie algebras of maximal rank

Speaker：Bakhrom Omirov (National University of Uzbekistan)

Time：2022年11月18日  10:30-11:30

Meeting IDZOOM ID：862 062 0549，Code：2022

https://us02web.zoom.us/j/8620620549?pwd=bGhsaG15WjRza2V3ZEN4TzJYZ1FZQT09

Abstract：The present talk is devoted to the description of local derivations and automorphisms on solvable Lie algebras of maximal rank. First, we present the general form of an automorphism on solvable Lie algebra of maximal rank. Namely, any automorphism can be represented as a composition of inner, diagonal and graph automorphisms.  We show that all local derivations and all local automorphisms of solvable Lie algebra of maximal rank are global, while there are examples of solvable Lie algebras of non-maximum rank with different behavior of local derivations and local automorphisms. We also apply the main results to the descriptions of local derivations and local automorphisms on standard Borel subalgebras of complex simple Lie algebras.

BioBakhrom Omirov is a professor at the National University of Uzbekistan. His research focused on non-associative algebras and superalgebras. In particular, he is one of the authors of the monograph devoted to the structure theory of Leibniz algebras. Bakhrom Omirov is a member of The World Academy of Sciences, which includes 66 countries), as well as Uzbek and American Societies. He is a winner of several prestigious fellowships (Fulbright, USA; INTAS, Belgium).

On the first cohomology group of Murray-von Neumann algebras

Speaker：Karimbergen Kudaybergenov (V.I. Romanovskiy Institute of Mathematics, Uzbekistan Academy of Sciences)

Time：2022年11月18日  15:30-16:30

Meeting ID：ZOOM ID：862 062 0549，Code：2022

https://us02web.zoom.us/j/8620620549?pwd=bGhsaG15WjRza2V3ZEN4TzJYZ1FZQT09

Abstract：This talk presents a full resolution of the problem stated by Ayupov in 2000 and partly restated in 2014 by Kadison and Liu. We explain a background of the Ayupov–Kadison–Liu Problem and its connection with general derivation theory in operator algebras starting with fundamental results due to Kaplansky, Kadison, Sakai and others. We shall cite and brief explain major results concerning derivations on algebras of unbounded operators and list results concerning some special cases of the problem. Finally, the main result yielding the full resolution will be stated.

Bio：Karimbergen Kudaybergenov is a head at the Karakalpak branch of V.I.Romanovskiy Institute of Mathematics, Uzbekistan Academy of Sciences. His research focused on operator algebras and mappings on non-associative algebras. Karimbergen Kudaybergenov is an influential expert in the studies of derivations of unbounded operator algebras, who is also an exceptionally prolific author publishing his results in top internationally recognized journals. The highest quality of his research contributions has been recognized in Uzbekistan. In 2017, he was awarded the State Prize of the first degree in the field of Science and Technology of the Republic of Uzbekistan. Further, in 2017, he was awarded an Honored Scientist of the Republic of Karakalpakstan.

Equilibrium programming: background and some new concepts

Speaker：Boris Budak （Moscow State University

Time：2022年11月17日  15:45-16:45,

Meeting ID：ZOOM ID：862 062 0549，Code：2022

https://us02web.zoom.us/j/8620620549?pwd=bGhsaG15WjRza2V3ZEN4TzJYZ1FZQT09

AbstractEquilibrium programming is a broad area of mathematics that studies mathematical models of numerous phenomena in natural sciences and economics. A typical situation is when exact values of functional Φ(v,w) are not available when finding the numerical solution to the  equilibrium programming problem and we have only their approximations. It is known that numerical models do not always work correctly in that situation, and different types of regularization must be applied. One of the best-known of these is Tikhonov’s regularization, which is usually used in processing approximate data. Some classic and new concepts of regularization will be discussed, a new regularized shooting model based on Tikhonov regularization for solving problems of equilibrium programming with inexact data will be given as an example.

BioBoris Budak is an associated professor of Faculty of Computational Mathematics and Cybernetics, Moscow State University. His Main Scientific Interests and Results including:

1. Extremal problems with disturbed data, optimal control, stabilization and regularization.

2. Developed and investigated a family of continuous methods for equilibrium programming problems solving, developed regularized analogues of these methods for the situation, when initial data is disturbed.

3. Created a new so-called “shooting” method for equilibrium programming problems solving, developed regularized analogue of it.

4. Solved some problems dedicated to a search of an operator with minimal norm, that guarantees a given solution of a linear operator equation in Hilbert spaces.

Complex cobordisms, the universal formal group, and theta divisors

Speaker：Victor Matveevich Buchstaber (Steklov Mathematical Institute, Russian Academy of Sciences)

Time：2022年11月11日  15:30-16:30

Meeting ID：ZOOM ID：862 062 0549，Code：2022

https://us02web.zoom.us/j/8620620549?pwd=bGhsaG15WjRza2V3ZEN4TzJYZ1FZQT09

Abstract: The talk is devoted to fundamental connections between algebraic topology, the formal groups theory and algebraic geometry.

The focus will be on the result of V.M. Buchstaber and A.P. Veselov, 2020. According to this result the exponent of the universal one-dimensional formal group is given by a series f(t) with the coefficient at t^{n+1}/ (n+1)! which is equal to the complex cobordism class of the theta divisor of a general (n+1)-dimensional abelian variety. We will discuss the applications of this result to well-known problems of algebraic topology and algebraic geometry, including the still open Milnor-Hirzebruch problem on the Chern numbers of irreducible smooth algebraic varieties.

The talk is designed for a wide audience, all the necessary concepts will be introduced.

Bio: Prof. Victor Matveevich Buchstaber is an expert in algebraic topology, geometric combinatorics, mathematical physics, founder of a large scientific school in topology and its applications, corresponding member of the Russian Academy of Sciences, chief scientific researcher of the Moscow Mathematical V.A.Steklov Institute, professor of the Moscow State M.V. Lomonosov University, Vice President of the Moscow Mathematical Society.

Conservative algebras

Speaker：Ivan Kaygorodov （University of Beira Interior）

Time：2022年11月04日  15:30-16:30

Meeting IDZOOM ID：862 062 0549，Code：2022

https://us02web.zoom.us/j/8620620549?pwd=bGhsaG15WjRza2V3ZEN4TzJYZ1FZQT09

Abstract: The class of conservative algebras was introduced in 1972 by I. Kantor. Roughly speaking, it is a class of algebras satisfying a "quasiidentity'' of degree 4. The class of conservative algebras includes many important varieties of algebras, such as associative algebras, Lie algebras, Leibniz algebras, Zinbiel algebras, Jordan algebras, etc. Conservative algebras and superalgebras have some similar properties to many well-known varieties of algebras. For example, they admit the Tits-Koecher-Kantor construction (TKK construction); each conservative algebra (and superalgebra) could be embedded in a suitable universal conservative algebra (or superalgebra). We will talk about some old and new results from this topic.

Bio: Ivan Kaygorodov got his Ph.D. in 2010 at the Sobolev Institute of Mathematics (Russia). He has worked as a postdoctoral researcher at the University of Sao Paulo (Brazil) and as an assistant professor at the Federal University of ABC (Brazil) for 10 years. Now he is a research fellow at the University of Beira Interior (Covilhã, Portugal). He is the Editor-in-Chief of Communications in Mathematics. His main area of research interest is in non-associative algebras.

Weak Leibniz algebras and transposed Poisson algebras

Time：2022年10月28日  14:00-15:00

Meeting ID：ZOOM ID：862 062 0549，Code：2022

https://us02web.zoom.us/j/8620620549?pwd=bGhsaG15WjRza2V3ZEN4TzJYZ1FZQT09

Abstract: Weak Leibniz algebras are defined by the following identities: $[a,b]c=2(a(bc)-b(ac))$ and $a[b,c]=2((ab)c-(ac)b).$ Any two-sided Leibniz algebra, in particular any Lie algebra is weak Leibniz. We show that polarization of any weak Leibniz algebra is transposed Poisson and conversely, depolarization of any transposed Poisson algebra is weak Leibniz. Well known that any simple Leibniz algebra is Lie. We construct simple weak Leibniz algebras that are not Lie.

Bio: Askar Jumadildayev is a professor of Kazakh-British Technical University. His research interests concern cohomologies and deformations of Lie algebras, N-commutators of vector fields, identities of non-associative algebras and operads theory.

SU-bordism: geometric representatives, operations, multiplications and projections

Speaker：Panov Taras (Moscow State University)

Time：2022年10月21日  15:00-16:00

Meeting ID：ZOOM ID：862 062 0549，Code：2022

https://us02web.zoom.us/j/8620620549?pwd=bGhsaG15WjRza2V3ZEN4TzJYZ1FZQT09

Abstract: The development of algebraic topology in the 1960s culminated in the description of the special unitary bordism ring. Most leading topologists of the time contributed to this result, which combined the classical geometric methods of Conner-Floyd, Wall and Stong with the Adams-Novikov spectral sequence and formal group law techniques that emerged after the fundamental 1967 work of Novikov.

Thanks to toric topology, a new geometric approach to calculations with SU-bordism has emerged, which is based on representing generators of the SU-bordism ring and other important SU-bordism classes by quasitoric manifolds and Calabi-Yau hypersurfaces in toric varieties.

We shall also discuss more specific topics related to SU-bordism. Namely we show that SU-linear operations in complex cobordism are generated by the well-known geometrical operations $\partial_i$. For the theory $W$ of $c_1$-spherical bordism, we describe SU-linear multiplications on W and projections $MU \to W$. We also analyse complex orientations on $W$ and prove results on the s-numbers of the coefficients of the corresponding formal group laws.

The talk is based on joint work with Zhi Lu, Ivan Limonchenko and Georgy Chernykh.

Bio: Panov Taras，Professor, Faculty of Mathematics and Mechanics, Moscow State University; Moscow Mathematical Society prize (2004); Shuvalov Prize of Moscow University (2010).

Personal Web Page: http://higeom.math.msu.su/people/taras/english.html.

Properties of polynomial maps and two-dimensional Jacobian conjecture

Speaker：Yucai Su （Tongji University）

Time：2022年10月14日  14:30-15:30 Beijing time

Meeting ID：ZOOM ID：862 062 0549，Code：2022

https://us02web.zoom.us/j/8620620549?pwd=bGhsaG15WjRza2V3ZEN4TzJYZ1FZQT09

Abstract: For any two polynomials on two variables with a nonzero Jacobian determinant, there corresponds a polynomial map known as a Keller map. In this talk, the speaker will report 3 properties of Keller maps, which are used to give a proof of the two-dimensional Jacobian conjecture in the speaker’s paper entitled a proof of 2-dimensional Jacobian conjecture'' at arXiv:1603.01867.

Bio: Yucai Su is a professor at Tongji University and Jimei University. He has successively worked as a visiting scholar and postdoctoral researcher at Queen Mary and Westfield College, the University of London, Concordia University, and the University of Quebec at Montreal for 7 years. His main research interests include Lie algebras, representation theory and Jacobian problem. In particular, he has studied the Jacobian Conjecture for eighteen years.  He is an editor of Algebra Colloquium and Journal of Mathematical Study, and published over 100 papers in Adv. Math., J. Eur. Math. Soc., Proc. London Math. Soc., Comm. Math. Phys., Math. Z., Israel J. Math., etc.  Recently, using the local bijectivity of Keller maps, he solved the 2-dimensional Jacobian Conjecture.

Speaker：Michael Batanin （Institute of Mathematics of Czech Academy of Science, Charles University, Prague

Time：2022年09月30日 16:30-17:30

Meeting IDZOOM ID：862 062 0549，Code：2022

https://us02web.zoom.us/j/8620620549?pwd=bGhsaG15WjRza2V3ZEN4TzJYZ1FZQT09

Abstract: Operads were introduced at the end of 1960s by Boardman, Vogt and P.May as spaces parametrising multivariable operations and their substitutions. In the 1990's however, it was realised that there are other interesting types of operads such as cyclic and modular operads of Getzler and Kapranov (motivated by TQFT development) and globular n-operads of Batanin parametrising higher categorical compositional structures. In 2015 Batanin and Markl introduced operadic categories in order to develop a consistent theory of operadic like structures. In my talk I explain what operadic category and associated category of operads are and why this is a very rich and useful new algebraic concept.

Bio: The speaker graduated from Novosibisk State University in 1983. He is currently a Senior Researcher at the Institute of Mathematics of Czech Republic, and a Professor of Charles University in Prague. He is specialising in Algebraic Topology, Category Theory, Operads and related topics.

International Frontiers of Mathematics

2022 International Conference on the Cooperation and Integration of Industry, Education, Research and Application

Sino-Russian Mathematics Center-Jilin University Base organize the conference Frontiers in Mathematics--2022 International Conference on the Cooperation and Integration of Industry, Education, Research and Application, from Sep. 26-Sep. 29, 2022.

The conference focuses on the following four topics: Numerical Methods and Analysis, Algebra and Applications, Dynamical Systems and Differential Equations with Applications, Control, Optimization and Data Science.

Zoom ID: 862 062 0549 Password: 2022

Speaker：张大军 上海大学

Time：2022年09月23日 10:30-11:30

Meeting ID：腾讯会议：309-266-962

Abstract: 这是一个关于“孤立波”的历史与发展的科普报告。1834年 John Scott Russell首次发现孤立波，1895年Korteweg和de Vries (KdV) 利用KdV方程描述了孤立波现象， 1965年 Kruskal 和 Zabusky在研究Fermi-Pasta-Ulam问题时发现并命名了“soliton” (孤立子), 两年以后Gardner-Greene-Kruskal-Miura 建立了反散射方法(Inverse Scattering Transform), 成为现代可积理论的起点。报告将回顾孤立波与可积系统在前150年(1834-1984)的历史，回顾期间(特别是1968-1984)出现的重要的可积模型以及重要的理论与方法进展。

Bio: 张大军，上海大学数学系教授，博士生导师。主要从事离散可积系统与数学物理的研究，包括离散可积系统的直接方法、多维相容性的应用、空间离散下的可积结构与连续对应等。曾访问Turku大学、Leeds大学、剑桥牛顿数学研究所、Sydney大学等学术机构。先后主持国家自然科学基金面上项目5项。目前担任离散可积系统国际系列会议SIDE (Symmetries and Integrability of Difference Equations)指导委员会委员(2012-)和国际期刊Journal of Physics A编委(2020-)。

Coarse geometry and operator algebras : a minicourse

Speaker：Yeong Chyuan Chung 博士后  Leiden University

Meeting ID腾讯会议：869-2118-6000，密码：3721

Abstract: Coarse geometry involves studying metric spaces by looking at them from far away, and it is important in areas of mathematics such as geometric group theory. In recent times, its interaction with operator algebras has also been an active area of research with applications to problems in topology and differential geometry. In this mini-course, we aim to introduce basic notions in coarse geometry and a class of operator algebras known as Roe algebras. Starting from coarse geometry, we will introduce basic definitions such as coarse embeddings and coarse equivalences, then we will introduce some coarse geometric invariants such as asymptotic dimension and property A. Next, we will introduce Banach algebras and C*-algebras with examples of these, then we will focus on Roe algebras and how they reflect the coarse geometry of the underlying metric spaces. Finally, we will briefly introduce operator K-theory and the coarse Baum-Connes conjecture involving the K-theory of Roe algebras.

 授课日期 Date of Lecture 课程名称（讲座题目） Name (Title) of Lecture 授课时间 Duration 参与人数 Number of Participants Sep 19, 2022 Introduction to coarse geometry: basic definitions and asymptotic dimension 19:30-20:30 30 Sep 20, 2022 Introduction to coarse geometry: property A 19:30-20:30 30 Sep 21, 2022 Banach algebras and C*-algebras with examples 19:30-20:30 30 Sep 22, 2022 Roe algebras I 19:30-20:30 30 Sep 26, 2022 Roe algebras II 19:30-20:30 30 Sep 27, 2022 Basic operator K-theory 19:30-20:30 30 Sep 28, 2022 K-theory of Roe algebras and the coarse Baum-Connes conjecture 19:30-20:30 30 Sep 29, 2022 A quick look at a counterexample to the coarse Baum-Connes conjecture 19:30-20:30 30

Bio: Yeong Chyuan Chung（钟永权），2017年博士毕业于美国德州农工大学, 主要从事粗几何、L^p算子代数、K-理论的研究。 近年来在J. Funct. Anal.，J. Noncommut. Geom.等杂志上发表多篇高水平论文。

Speaker：Andrey Dorogovtsev professor（Institute of Mathematics，NAS Ukraine

Meeting ID：Zoom会议 ID：会议号：852 4434 8793，密码：075030

Abstract: This course aims to provide a solid introduction on some advanced numerical methods and its applications. The first part of the course will introduce the definition of local times and Gaussian functionals, then discuss some properties when local times as a Gaussian functionals. And the second part of the course is devoted to introduce Hausdorff measure and dimension, then use the Hausdorff measure and dimension to discuss sef-intersections set of Brownian motion. Professor Andrey will give students some time to understand the knowledge and give some small questions about the lecture.

 授课日期 Date of Lecture 课程名称（讲座题目） Name (Title) of Lecture 授课时间 Duration (Beijing Time) 参与人数 Number of Participants 2022-09-19 Local times and sets of values of random fields 16:00-17:00 30 2022-09-21 Gaussian white noise and functionals from it 16:00-17:00 30 2022-09-26 Local times as a Gaussian functionals 16:00-17:00 30 2022-09-28 Local nondeterminism for Gaussian random fields 16:00-17:00 30 2022-10-03 Hausdorff measure and dimension 16:00-17:00 30 2022-10-05 Haussdorf dimension for sef-intersections set of Brownian motion 16:00-17:00 30

Bio: Andrey Dorogovtsev教授是乌克兰国家科学院通讯院士，乌克兰国家科学院数学所随机过程理论系主任，主要从事概率论及其相关领域研究，是乌克兰概率论研究方向学术领军人物之一。Andrey Dorogovtsev教授是乌克兰与德国、乌克兰与俄罗斯等国家联合项目的乌方负责人。同时，Andrey Dorogovtsev教授是《Theory of Stochastic Processes》《Ukraine Mathematical Journal》等杂志的编委。

Noncommutative differential geometry and quantum effects of gravity

Speaker：张晓（中国科学院数学与系统科学研究院）

Time：2022年09月16日 10:30-11:30

Meeting ID：腾讯会议 ID：602-653-169

Abstract: We provide a rigorous theory of noncommutative metrics and curvatures in frame of deformation quantization. In terms of them, we are able to propose the noncommutative Einstein field equations. We show that the deformation of classical pp-waves are exact solutions of vacuum field equations. We also find that the quantization of spherically symmetric metrics is renormalizable and the deformation of classical Schwarzschild solution is the quantum black hole solution which does not depend on time and can not be evaporated. The talk is based on the early joint works with Chaichian, Tureanu, D. Wang, R.B. Zhang as well as H. Gao recently.

Bio: 张晓，中国科学院数学与系统科学研究院数学研究所研究员，国家杰出青年基金及中科院百人计划获得者。现任广西大学君武学者和广西八桂学者，广西数学研究中心执行主任。从事广义相对论的数学研究，在广义相对论正能量问题及引力量子化的非交换几何理论上作出了系统性的贡献。

Higher algebraic structures-a minicourse

Speaker：Camilo Andres Angulo Santacruz（Universidade Federal Fluminense）

Meeting ID：ZOOM ID：862 062 0549   Password：2022

https://zoom.us/j/8620620549?pwd=bGhsaG15WjRza2V3ZEN4TzJYZ1FZQT09

Course Abstract：“Higher structure” is a term used loosely to refer to a large collection of structures that share a common theme. Suppose a mathematical structure consists of a collection of sets, functions between them, and some equations that the latter shall verify. Think of group structures, for instance, as the sets G, GxG, and the singleton, together with three functions (the multiplication, the unit, and the inverse) that verify the usual axioms of a group, which are equations relating them(!). The common idea behind higher structures is that they roughly are like mathematical structures, but replacing sets by homotopy types, equations by homotopies, and adding higher-order homotopies to enforce coherence.

Higher structures have an intricate history and abound in mathematics. We will focus on three types of higher structures that have algebraic flavor.In what follows we describe the plan of the lectures. We will start by giving a bit of a panoramic perspective on the history and emergence of the higher structures we will consider. After going through some preliminaries, we proceed to study them one by one, starting with the so-called L-infinity algebras, continuing with stacky groupoids, and closing with Lie n-groupoids. In each module, we go through definitions, examples, and main constructions. We conclude by trying and relating these structures among them and by giving an outlook for the directions in which these generalize by touching upon some recent research topics.

Bio：Camilo Andres Angulo Santacruz is a post doctor from Universidade Federal Fluminense, Brazil. He mainly study Poisson geometry and higher structures.

Speaker：闫振亚（中科院数学院系统所）

Time20220909 10:30-11:30

Meeting ID：腾讯会议 ID：737-700-086

Abstract: 不同于通常的孤子(soliton), 怪波（rogue wave/rogon）拥有巨大的能量，也被称为畸形波、巨波、极端波等。它最早出现在深水海洋中，后来人们发现很多自然科学中也存在怪波现象，如光学、Bose-Einstein凝聚态、等离子体物理、大气科学、生物学和金融市场等。从某种意义来说，社会科学中的突发问题也属于怪波范畴。本报告介绍线性和非线性科学问题中怪波的背景、发展和挑战等。另外讨论怪波产生的一些物理机理等。

Bio: 闫振亚，中科院数学院系统所研究员，主要研究可积系统理论、怪波、PT对称、智能数学物理及交叉应用等。2019年获得国家自然科学基金杰出青年基金。

Operators on the universal enveloping algebras and quantisation of the argument shift method

Speaker：Georgy Sharygin（Lomonosov Moscow State University）

Time20220909 21:00-22:00

Meeting ID：ZOOM ID：862 062 0549   Password：2022

https://zoom.us/j/8620620549?pwd=bGhsaG15WjRza2V3ZEN4TzJYZ1FZQT09

Abstract:  Argument shift method is an important and simple method to generate large commutative subalgebras in Poisson algebras, in particular in the algebras of functions on coadjoint representation of a Lie algebra. In the last 20 years a considerable in finding "quantized version" of such algebras was achieved: in the papers of Rybnikov, Molev and others one can find many examples of commutative subalgebras in the universal enveloping algebras of different Lie algebras, that "raise" the subalgebras, obtained by the argument shift method. However these subalgebras are constructed by "quantizing" concrete sets of generators in the "classical" argument shift subalgebras, and no general construction of "shifting" in the universal enveloping algebras is known. In my talk I will discuss a potential "quantum counterpart" of the shift in a particular case of the Lie algebra gl_n. It is based on the use of "quasi-derivations" of Ugl_n, introduced by Gourevitch and Saponov. I will describe these operators and discuss their relation with other constructions. I will also discuss the experimental data that supports the conjecture that one can define the quantum shift of the argument using these operators.

Bio: Georgy Sharygin got his PhD from Moscow State University in 2000, and since that time he has been teaching Mathematics at all levels from High school to the PhD programs. He was invited speaker at many international conferences, was many times invited researcher in various international institutes. His research interests include deformation quantisation, non commutative geometry, topology, differential geometry and integrable systems.

The category of 2D rational CFT's

Speaker：孔良（南方科技大学）

Time20220902 21:00-22:00

Meeting ID：腾讯会议 ID：939-656-494

Abstract:  In this talk, I will review the categorical study of 2D rational CFT's and topological defects in the last two decades. In the end, I will show how to use it to describe the category of 2D rational CFT's.

Bio: 孔良，南方科技大学深圳量子科学与工程研究院研究员。1994年于中国科学技术大学获得物理学士学位，2005年于美国Rutgers，the State University of New Jersey获得数学博士学位。主要研究拓扑量子场论和共形场论的数学理论，以及在拓扑物质态中的应用。

Speaker：刘青平（中国矿业大学）

Time20220819 10:00-11:00

Meeting ID：腾讯会议 ID：721-493-311

Abstract:  这是关于Darboux变换的一个科普报告。我们将从Jean Gaston Darboux发表于1882年一篇短文谈起，介绍什么是Darboux变换、构造Darboux变换的方法以及它在可积系统理论中的应用。

Bio: 刘青平，国务院政府特殊津贴获得者，北京市高等学校教学名师，1992年获英国Leeds大学博士学位，曾在中国科学院理论物理研究所和西班牙Complutense大学做博士后，现为中国矿业大学（北京）教授。从事可积系统理论及其应用研究。更多信息见个人主页：https://lxy.cumtb.edu.cn/info/1067/1238.htm

Morse指标定理简介

Speaker胡锡俊（山东大学）

Time2022年08月12日 10:00-12: 00

Meeting ID：腾讯会议 ID：324-276-209

Abstract:  Morse指标定理源于对测地线的研究，它将Morse指标表为测地线共轭点的重数之和。在本次演讲中我们将回顾Morse指标定理的经典结论并介绍最新的进展。

Bio: 胡锡俊，山东大学教授。1997年7月和1999年7月在吉林大学分别获得学士学位和硕士学位，2002年7月在南开大学获得博士学位。2014年获得国家杰出青年基金，主要研究方向为哈密顿系统与非线性分析。在天体力学中周期解的稳定性问题，哈密顿系统指标理论及一类反应-扩散方程行波解的研究中做出了创新性的工作。

Symmetries: from groups to tensor categories

SpeakerAlexei Davydov（Ohio University

Time2022年08月12日 16:00-17: 00

Meeting ID：ZOOM ID：862 062 0549， Password：2022

https://us02web.zoom.us/j/8620620549?pwd=bGhsaG15WjRza2V3ZEN4TzJYZ1FZQT09

Abstract: Groups are mathematical ways of talking about symmetries. From its beginning Group Theory was driven by the idea of symmetry and its applications (e.g. Galois' proof of unsolvability of a quintic). One of the most spectacular applications of Group Theory was the classification of crystals done at the end of the 19th century. In the middle of the 20th century Group Theory was used to describe all known states of matter. Experimental developments of the condensed matter physics at the end of the 20th century were not fitting the standard Group Theory scheme. They forced us to generalize the mathematical formulation of symmetry. The talk will be about this generalized notion, the one of tensor category.

Bio: Alexei Davydov is a Professor of Department of Mathematics, Ohio University. He mainly works on category theory and homological algebra.

Gravity properad, moduli spaces M_g,n, and string topology

Speaker：Sergei Merkulov   University of Luxembourg

Time2022年08月05日 16:00-18: 00

Meeting ID：ZOOM ID：862 062 0549

https://us02web.zoom.us/j/8620620549?pwd=bGhsaG15WjRza2V3ZEN4TzJYZ1FZQT09

Abstract: Using Thomas Willwacher’s twisting endofunctor, and Kevin Costello’s theory of partially compactified moduli spaces of algebraic curves of arbitrary genus with marked points, we introduce a new dg properad which contains Ezra Getzler’s operad controlling genus zero moduli spaces. We discuss its applications in the theory of moduli spaces M_g,n, and in string topology.

Bio: Sergei Merkulov is a Professor at the University of Luxembourg. He worked previously at the Russian Academy of Sciences, the Glasgow University (UK) and the Stockholm University (Sweden). He works on category theory, homological algebra and Differential geometry.

Thick morphisms of supermanifolds and homotopy algebras

Speaker：Theodore Voronov   University of Manchester

Time2022年07月29日 16:00-18: 00

Meeting IDZOOM ID：862 062 0549

https://us02web.zoom.us/j/8620620549?pwd=bGhsaG15WjRza2V3ZEN4TzJYZ1FZQT09

Abstract: Supergeometry can be used as a unifying language for many algebraic and differential-geometric constructions. Particular role here is played by homological vector fields, i.e. odd vector fields Q satisfying Q^2=0. They can be useful for describing “higher” or “homotopy” analogs of Poisson brackets. Recently I discovered a generalization of the notion of a smooth map (called by me “thick morphisms”) giving NONLINEAR pullbacks on smooth functions. “Thick morphisms” can in particular provide L_infinity morphisms for homotopy Poisson structures. There are other interesting connections, e.g. with Fourier integral operators. Thick morphisms also provide a nonlinear analog of classical functional-algebraic duality.

Bio: Dr Theodore Voronov is a Professor in Pure Mathematics at the University of Manchester (UK). His research interests are on the crossroads of algebra, differential geometry, topology and mathematical physics; in particular, geometry of supermanifolds and its applications. See more at

http://personalpages.manchester.ac.uk/staff/theodore.voronov.

Representations of the Fermion-Virasoro algebras

Speaker：赵开明 Wilfrid Laurier University

Time2022年07月15日 09:00-11:00

Meeting ID

https://meeting.tencent.com/dm/aEOWDPUh24oM

Abstract: We introduce Fermion algebras F and the Fermion-Virasoro algebras. They are infinite-dimensional Lie superalgebras. The progress on simple smooth modules and simple Harish-Chandra modules over these algebras will be discussed.

Bio: 赵开明，加拿大Wilfrid Laurier大学教授，主要研究方向为李代数。主持多项国家自然科学基金, 及加拿大NSERC基金。他在 Adv. Math., Tran. AMS, J. Lond. Math. Soc., J. Algebra 等国际刊物上发表学术论文100多篇。

Rota-Baxter bisystems and mixed bialgebras

Speaker：Abdenacer MakhloufUniversité de Haute Alsace

Time20220708 16:00-17:00

Meeting ID

ZOOM ID：862 062 0549Code2022

https://us02web.zoom.us/j/8620620549?pwd=bGhsaG15WjRza2V3ZEN4TzJYZ1FZQT09

Abstract: In this talk, we deal with a generalization of the concept of Rota-Baxter operators defined by T. Brzezi´nski and called Rota-Baxter systems which appeared in [J. Algebra 460(2016):1- 25]. We provide a dual version and then consider a generalization to bialgebras, we introduce the notion of Rota-Baxter bisystem and construct various examples. On the other hand, we introduce a new type of bialgebras (named mixed bialgebras) which are consisting of an associative algebra and a coassociative coalgebra satisfying the compatible condition determined by two coderivations. We investigate coquasitriangular mixed bialgebras and the particular case of coquasitriangular infinitesimal bialgebras, where we give the double construction. This is a joint work with Tianshui Ma and Sergei Silvestrov.

Bio: Abdenacer Makhlouf is a Professor and the head of Mathematics Department at University of Haute Alsace, Mulhouse, France. His research covers structure, representation theory, deformation theory and cohomology of various types of algebras, including Nonassociative algebras, Hopf algebras and n-ary algebras.

Kahler-Ricci flow on smooth minimal models

Speaker：张振雷（首都师范大学）

Time20220701 10:00-12:00

Meeting ID腾讯会议 ID：780-765-137

To Join Tencent Meeting: https://meeting.tencent.com/dm/5cjuobQFgOpb

AbstractIt is a survey talk on the long-time behavior of a Kahler-Ricci flow on a smooth manifold with a semi-ample canonical line bundle.

Bio张振雷，首都师范大学数学科学学院教授。2003年本科毕业于吉林大学数学科学学院；2008年博士毕业于南开大学陈省身数学研究所，导师方复全教授。2018年获国家自然科学基金杰出青年科学基金资助主要研究Ricci流、Kahler-Ricci流。

Speaker：徐晓平中国科学院大学

Time20220624 14:00-16:00

Meeting ID：腾讯会议 ID：703-956-224

To Join Tencent Meetinghttps://meeting.tencent.com/dm/gtlAO1KvxQLo

Abstract这是一个科普型报告。我们从“什么是数学”谈起。然后是：素数的故事，拉马驽金的故事，分隔函数，KdV方程，量子物理的基本数学模型。之后，我们讲：数学的残缺美，一些挑战性问题以及本人的一些研究体验。

Bio徐晓平，中国科学院大学教授，中国科学院数学研究所所长。1992年在美国Rutgers大学取得博士学位，师从著名的李理论专家James Lepowsky Robert Lee Wilson。之后在香港科技大学工作十年。2002年回到中国科学院数学研究所工作， 2014年开始兼任中国科学院大学教授，自20223月起，任中国科学院数学研究所所长。获宝钢优秀教师奖。他在李代数、顶点算子代数（共形场论）和偏微分方程的代数解法等相关领域的研究中做出了重要贡献。

Speaker：雷逢春大连理工大学

Time20220624 10:00-12:00

Meeting ID685-963-603

To Join Tencent Meetinghttps://meeting.tencent.com/dm/49Yn9DtKVB4q

Abstract拓扑学是当代核心数学的一个重要前沿领域，其渊源可追溯到欧拉早期的工作（1836年，哥尼斯堡七桥问题的解答）。拓扑学奠基于19世纪末, 20世纪取得了梦幻般的发展, 进入21世纪更加兴旺发达。本报告将对拓扑学的发展作一个跨越世纪的通俗概要浏览, 重点介绍低维拓扑学的发展，即二、三和四维流形拓扑学的主要成就。

Bio雷逢春，199012月博士毕业于吉林大学基础数学专业，研究方向为低维拓扑，现为大连理工大学数学科学学院教授、博士生导师。长期从事三维流形拓扑方面的研究工作，多次承担国家自然科学基金面上项目、重点项目和海外及港澳学者合作研究基金(延续)项目的研究工作。曾于1997年荣获国家教委科技进步二等奖(排名3)2001年获黑龙江省杰出青年科学基金，2002年入选教育部“跨世纪优秀人才培养计划”。现为中国数学会常务理事，辽宁省数学会副理事长，大连市数学学会理事长。

Factorization of Shapovalov elements

Speaker：Andrey MudrovMoscow Institute of Physics and Technology and University of Leicester

Time20220617 15:00-17: 00

Meeting ID：ZOOM ID：862 062 0549, Password:2022

AbstractA classical result of J. Bernstein, I. Gelfand and S. Gelfand says that a singular vector in a Verma module over a simple complex Lie algebra can be obtained from its highest vector by applying a product of special elements of the negative nilpotent subalgebra called Shapovalov elements. We provide explicit formulas for those elements, and hence for singular vectors of the Verma modules, expressing them through certain matrix elements of the inverse contravariant Shapovalov form.

BioThe speaker is currently an Associate Professor and a Senior Researcher at the Center of Fundamental Mathematics in MIPT, and an Honorary Lecturer at the University of Leicester. He is specializing in quantum groups, deformation quantization and related topics.

Speaker：张影（苏州大学）

Time20220610 10:00-12:00

Meeting ID564-626-700

To Join Tencent Meetinghttps://meeting.tencent.com/dm/p7VBNfhblItm

Abstract在与李祥飞的合作工作中，我们研究具有最大对称性的完备的双曲环面上的闭测地线的性质，证明一般闭测地线的迹多项式的正性，一些简单闭测地线长度的单调性，并提出简单闭测地线的迹的凸性猜测，以及一般闭测地线的迹多项式系数的对数凹性猜测。

Bio张影，1985.9-1999.5 吉林大学数学系本研学习、任教，1999.5-2004.7 新加坡国立大学读研，2006.3-2007.2 巴西国家数学所(IMPA)博士后，2009.6至今，苏州大学数学科学学院教授。从事几何拓扑学研究。

Speaker：段海豹 (中国科学院数学与系统科学研究院)

Time2022527 10:00-12:00

Meeting ID899-680-387

To Join Tencent Meetingmeeting.tencent.com/dm/Il9TkCVA4hAL

Abstract同调论是20世纪数学所诞生的一项新技术，是当代几何、拓扑、分析学的有力工具。报告通过 Riemann, Poincare, Brouwer, Hopf 等开拓者们的相关工作介绍，回顾同调论的背景、起源、以及发展历程。

Bio段海豹，中国科学院数学与系统科学研究院研究员，19773月－19851月，在吉林大学数学系学习，获理学学士、硕士学位；19877月，在北京大学获博士学位。从事代数拓扑，微分拓扑和代数几何的教学、研究工作。 他在2005年获中国数学会陈省身数学奖，2010年获国家自然科学二等奖。

Lie 2-algebras from geometric structures

Speaker：Zhangju LIU

Time2022.5.13 14:00-16:00

Meeting ID347-371-151

To Join Tencent Meetinghttps://meeting.tencent.com/dm/rx9v5zMU7xnV

AbstractThe notion of Lie 2-algebras is introduced as categorification of Lie algebras, Which is one of the fundamental objects in higher Lie theory and has close connection with strongly homotopy Lie algebras. The Lie 2-algebra structure has enjoyed significant applications in both geometry and mathematical physics. Strict Lie 2-algebras are equivalent to Lie algebra crossed modules, which are classified by the third cohomology of a Lie algebra.

In this talk, we’ll review several Lie 2-algebras that come from geometric structures, namely, 2-plectic manifolds; Courant algebroids; homotopy Poisson manifolds and affine structures on Lie groupoids. A 2-plectic structure on a manifold is a nondegenerate closed 3-form. There is a Lie 2-algebra structure on functions and Hamiltonian 1-forms of a 2-plectic manifold A Courant algebroid is a vector bundle together with a bilinear form, a skew-symmetric bracket and an anchor map. The bracket satisfies the Jacobi identity up to a coboundary, which generates a Lie 2-algebra on the section space of the bundle and functions on the base manifold. Parallel to the fact that there is a one-to-one correspondence between Lie algebra structures on a vector space and linear Poisson structures on the dual space, there is a one-to-one correspondence between Lie 2-algebra structures on a 2-vector space and linear homotopy Poisson structures on the dual 2-vector space. On a Lie groupoid, vector fields that are compatible with the groupoid multiplication are called multiplicative. Multiplicative vector fields with the Schouten bracket form a Lie algebra, which is not invariant under the Morita equivalence of Lie groupoids. To define vector fields on a differentiable stack, one needs to extend the Lie algebra to a Lie 2-algebra formed by affine vector fields on a Lie groupoid, which is Morita invariant.

Bio刘张炬，北京大学/河南大学教授，19821月本科毕业于吉林大学，19866月在北京大学获得博士学位。1999年获得国家杰出青年基金。主要从事数学物理、Poisson几何等领域的研究。曾入选教育部跨世纪优秀人才支持计划，2004年获得教育部自然科学一等奖。

Speaker：Pavel Kolesnikov (Sobolev Institute of Mathematics)

Time2022.5.6 10:00-12:00

Meeting ID862 062 0549

To Join Zoom Meetinghttps://us02web.zoom.us/j/8620620549?pwd=bGhsaG15WjRza2V3ZEN4TzJYZ1FZQT09

AbstractWe will observe the matching method in the algebraic discrete Morse theory which provides us a powerful tool for finding Anick resolutions for associative algebras defined by generators and relations. We apply this method to find reduced Hochschild cohomologies of associative conformal algebras in order to study their relations with the cohomologies of Lie conformal algebras. In particular, we evaluate the Hochschild cohomology groups for the universal associative envelope U(3) of the Virasoro Lie conformal algebra.

BioPavel Kolesnikov got his PhD in 2002 in Novosibirsk State University (NSU) and joined Sobolev Institute of Mathematics. Now he is a research fellow of the Institute and professor in the NSU. His main area of research interests is in the structure and combinatorial theory of associative and non-associative algebras, conformal and vertex algebras.

On the cobar-construction for non-simply connected spaces

Speaker：Andrey Lazarev ( Lancaster University )

Time：2022.04.22 16:00-18:00

Meeting ID862 062 0549

To Join Zoom Meetinghttps://us02web.zoom.us/j/8620620549?pwd=bGhsaG15WjRza2V3ZEN4TzJYZ1FZQT09

AbstractThe cobar-construction produces a differential graded (dg) algebra out of a dg coalgebra. When applied to the coalgebra of simplicial chains on a simply-connected space X, the resulting dg algebra models the chain algebra on the based loop space of X. This is a classical result of Adams and it has been known for over 60 years. In a recent breakthrough development, American mathematicians Rivera and Zeinalian removed the simple-connectivity assumption.  In this talk, I will explain Rivera-Zeinalian’s result, discuss its generalizations and connections with infinity-categories.

BioAndrey Lazarev is a professor of pure mathematics in the University of Lancaster. His recent research deals with homotopy theory of differential graded algebras and categories, derived categories and higher phenomena. It has applications in rational homotopy theory, theory of operads and operadic algebras, algebraic topology and pure algebra. Andrey Lazarev is the Managing Editor of the journalBulletin of the London Mathematical Society》， as well as a Member of the Editorial Board of  the journalHigher_Structures》.

Boson-Fermion Correspondence and Its Applications to Integrable Hierarchies Revisited From The Point of View of Representation Theory and Random Walks

Speaker：Jian Zhou

Time2022.04.15 10:00-12:00

Meeting ID694-475-243

To Join Tencent Meetinghttps://meeting.tencent.com/dm/dbl4pDJLd3zS

AbstractWe revisit the boson-fermion correspondence and its applications to integrable hierarchies via representation theory of symmetric groups. This makes it natural to consider random walks on various diagrams and graphs related to symmetric groups. Random partitions, hypergeometric tau-functions and weighted Hurwitz numbers are then brought together under a unified probabilistic treatment, rooted in their connections to the fermionic Fock space. Various approaches to the representation theory of symmetric groups all turn out to be useful in this treatment. They include: the new approach of Okounkov and Vershik, the Hopf algebra approach of Zelevinsky, and the lambda-ring approach of Knutson. A connection to the interpolating statistics in the study of fractional quantum Hall effect will also be explained.

Bio周坚，清华大学数学科学系教授，2005年国家杰出青年基金获得者、2009年入选国家“百千万人才工程”。他的研究领域为黎曼面的模空间与霍奇积分，拓扑场论，微分几何，弦理论等。周坚教授通过对超弦理论中Vafa学派的工作中出现的一些数学问题的研究，揭示了一些不同的数学分支之间的内在联系，他与合作者完成的“Marino-Vafa猜想的证明”入选2004年度“中国高校十大科技进展”。

Heegaard splitting: a survey

Speaker: 邱瑞锋 (华东师范大学)

Time：2022年04月08日 10:00-12:00

Meeting：#腾讯会议：680-593-921

https://meeting.tencent.com/dm/lxemeq0TOyx1

Abstract: Heegaard分解是紧致三维流形上普遍存在的组合拓扑结构，在三维流形理论的研究中起到了重要的作用。吉林大学是我国最早从事这一领域研究的研究群体，并直接或间接地培养了一批这一领域的专家学者。这个报告将介绍这一领域的国内外发展历史及现状。

Bio：邱瑞锋，华东师范大学教授，主要从事三维流形及纽结理论的研究，代表性工作有：（1）证明了Heegaard分解理论中的Gordon猜想，（2）构造了纽结洞数理论中的Morimoto猜想的反例等。

Orbifold theory and modular extensions

Speaker: 董崇英 美国加州大学Santa Cruz 分校

Time：2022-03-25 10:00-12:00

Abstract: Orbifold theory studies a vertex operator algebra V under the action of a finite automorphism group G.  The main objective is to understand the module category of fixed point vertex operator subalgebra V^G.  We prove a conjecture by Dijkgraaf-Pasquier-Roche on V^G- module category if V is holomorphic. We also establish a connection between rational orbifold theory and minimal modular extensions. Our work is based on the previous results on modular extensions by Drinfeld-Gelaki-Nikshych-Ostrik and Lan-Kong-Wen. This is a joint work with Richard Ng and Li Ren.

Bio: 董崇英，美国加州大学Santa Cruz分校终身教授，国际上无限维李代数和顶点算子代数领域最杰出的数学家之一,多年来一直从事无穷维李代数、顶点算子代数、Orbifold理论以及广义月光等方面的研究。在Acta Math.、Duke Math. J.、Adv. Math.、Comm. Math. Phys.等国际著名期刊发表论文100多篇，总引用超过3000次，其中包括菲尔兹奖获得者Drinfeld、Zelmanov和Borcherds以及著名数学家如Beilinson和Kac等人的重要引用。主持多项美国自然科学基金，并担任杂志Algebra Colloquium的主编以及Science China Mathematics等多个杂志的编委。
Meeting：128-767-072加入会议：
https://meeting.tencent.com/dm/hyMIOAPeEsWf

Deformations of Symplectic Foliations

Speaker: Marco Zambon (KU Leuven)

Time: 2022.03.04  20:00-22:00

Location： Zoom

ID：862 062 0549

Meeting：https://us02web.zoom.us/j/8620620549?pwd=bGhsaG15WjRza2V3ZEN4TzJYZ1FZQT09

Abstract:

Symplectic foliations and regular Poisson structures are the same thing. Taking the latter point of view, we exhibit an algebraic structure that governs the deformations of symplectic foliations, i.e. which allows to describe the space of symplectic foliations nearby a given one.  Using this, we will address the question of when it is possible to prolong a first order deformation to a smooth path of symplectic foliations. We will be especially interested in the relation to the underlying foliation. This is joint work with Stephane Geudens and Alfonso Tortorella.

Bio:

Marco Zambon is an associate professor at KU Leuven, Belgium. He works on topics related to Poisson geometry, in particular on those related to foliations, deformations and Lie theory.

Diophantine approximations

SpeakerNikolay Moshchevitin (Moscow State University)

Location：Zoom

ID：894 9789 1576

Lecture1. Continued fractions.
2022.01.19， 13：30-15：00

Representation of real numbers as continued fractions. Approximation by convergents, Perron's formula.
Irrationality measure function.
Lagrange and Dirichlet spectra. Minkowski diagonal continued fraction and the related spectrum. Geometry of continued fractions algorithm.

Lecture2. Distribution of Farey fractions.
2022.01.20， 13：30-15：00

Elements of basic number theory. Euler and Moebius functions.
Integral representation of greatest common divisor. Counting the number of reduced fractions in [0,1].
Fraenel's theorem. Relation to Riemann zeta-function.

Lecture3. Farey tree and Minkowski function.
2022.01.26， 13：30-15：00

Stern-Brocot sequences. Minkowski question-mark function.
Salem's theorem on the derivative. Fixed points problem. An analog to Fraenel's theorem.
Fourier-Stieltjes coefficients.

Lecture4.Multidimensional approximation.
2022.01.27， 13：30-15：00

Simultaneous approximation to real numbers. Linear forms close to xero.
Basic laws of approximation. Best approximations and phenomenon of degeneracy of dimension.
Diophantine exponents and Jarnik's inequalities.

Bio： Nikolay Moshchevitin教授现就职于莫斯科国立大学，研究兴趣为Geometry of numbers, geometric theory of Diophantine approximations, ergodic and combinatorial theory of numbers, theory of dynamical systems。共发表论文70余篇，超过400次引用。于1998年获得俄罗斯联邦国家奖

Geometry of Gaussian random curves

SpeakerAndrey Dorogovtsev（Institute of Mathematics，NAS Ukraine）

Location：Zoom

ID：858 7772 7123

Abstract:

This course aims to provide a solid introduction on the geometry of Gaussian random curves. Since the theory of geometry of Gaussian random curves is based on the concept of Gaussian random process and fields, the first part of the course will be devoted to some properties of this process and fields. And the second part of the course is devoted to discussion of geometry of Gaussian random curves like the Self-intersection local times for planar Brownian motion and the hitting probabilities for planar Broownian motion. Professor Andrey will give students some time to understand the knowledge and give some small questions about the lecture.

Time：

Lecture 1: Gaussian random processes and fields. Main examples

In this lecture we give the definition of Gaussian random processes and fields. Also, we will give some examples to understand this.

Lecture 2: Smoothness of Gaussian random fields

In this lecture we discuss the smoothness of Gaussian random fields, and we can get some properties on Gaussian random fields.

Lecture 3: Euler characteristic of the subsets in Euclid space

In this lecture we give the definition of Euler characteristic which in defined on Euclid space, it is topological invariant.

Lecture 4: Rice formula and asymptotic of tales for supremum of Gaussian random fields

In this lecture we give the Rice formula and discuss the asymptotic of tales for supremum of Gaussian random fields.

Lecture 5: Trajectory of Brownian motion as a random curve. Basic properties

In this lecture we discuss the trajectory of Brownian motion and give some basic properties about this.

Lecture 6: Self-intersection local times for planar Brownian motion

In this lecture we discuss the investigation of the local times of self-intersection as the most important geometric characteristics for planar Brownian motion.

Lecture 7: Hitting probabilities for planar Brownian motion

In this lecture we discuss the hitting probabilities and how we use this to describe the trajectory of planar Brownian motion.

Lecture 8: Tube formula for planar Brownian motion

In this lecture we give the Tube formula for planar Brownian motion, and use it to help us learn the trajectory of Brownian motion.

Bio：

Andrey Dorogovtsev教授是乌克兰国家科学院通讯院士，乌克兰国家科学院数学所随机过程理论系主任，主要从事概率论及其相关领域研究，是乌克兰概率论研究方向学术领军人物之一。Andrey Dorogovtsev教授是乌克兰与德国、乌克兰与俄罗斯等国家联合项目的乌方负责人。同时，Andrey Dorogovtsev教授是《Theory of Stochastic Processes》、《Ukraine Mathematical Journal》等杂志的编委。

Knot theory

SpeakerVassily Olegovich Manturov（Moscow Institute of Physics and Technology）

Time：2022年1月

LocationTencent Meeting

Room Number:614-9548-1864

Abstract:

Lecture1.

Reidemeister moves. Colouring invariants, and the linking number.

2022/01/06 18:00-19:00

Abstract:

We will introduce diagrams of knots and links. We use the diagrams to build two invariants of links: Coloring invariant and the linking number.

Lecture2.

The Kauffman bracket, the Jones polynomial.

2022/01/09 18:00-19:00

Abstract:

We will use Kauffman bracket to prove that Jones polynomial is a link invariant.We will compute some examples and prove the Kauffman-Murasugi-Thistlethwaite Theorem.

Lecture3.

Fundamental group. The knot group.

2022/01/13 18:00-19:00

Abstract:

We will define a famous link invariant: the fundamental group of the knot complements. We will show that this group is not trivial if the knot is not trivial.

Lecture4.

The knot Quandle is a complete knot invariant.

2022/01/16 18:00-19:00

Abstract:

Matveev and Joyce defined a knot invariant, the knot quandle.  This is a complete invariant. We can obtain many invariants from the knot quandle, for example, the knot group and coloring invariant.

Lecture5.

The braid groups

2022/01/20 18:00-19:00

Abstract:

We define the braid group. The action of the braid group on Aut(F_{n}) is complete.We will also discuss Markov Theorem and Alexander Theorem.

Lecture6.

The Alexander polynomial.

2022/01/23 18:00-19:00

Abstract:

We will introduce several ways to define the Alexander polynomial.

Lecture7.

Vassiliev invariant

2022/01/27 18:00-19:00

Abstract:

We will introduce the Vassiliev invariant and prove that “polynomial” invariant are all come from the Vassiliev invariant.

Lecture8.

Khovanov homology

2022/01/30 18:00-19:00

Abstract:

Khovanov homology is a categorification of the Jones polynomial, in the sense that its Euler characteristic is the Jones polynomial.

Bio：Professor Vassily Olegovich Manturov is from Moscow Institute of Physics and Technology. His research interest is low dimensional topology and knot theory.  He has published more than 150 papers and got more than 1500 citations. He got "Professor of RAS" in 2016 and he is one of the Managing Editors of the "Journal of Knot Theory and Its Ramifications". He has published many books, for instance, 《Parity in knot theory and graph-links. Contemporary Mathematics. Fundamental Directions》，《Low-dimensional Topology and Combinatorial Group Theory》，《Virtual Knots. The State of the Art》 and 《Knot Theory》.  He held many international conferences, such as "4-th Russian China Russia-China on Knot theory and Related topics" and three International Conferences in the Mathematical Institute (Oberwolfach) on knot theory and low-dimensional topology".

Rota-Baxter operators, skew braces and Yang-Baxter equation

Speaker：Valeriy Bardakov

Time：2021.12.17 15:00--17:00

Location：Zoom

Meeting ID: 862 062 0549

Meeting：https://us02web.zoom.us/j/8620620549?pwd=NUhCMWpuTG9Od1RMNjhEdkdwTzlsUT09

Abstract:

Bio：Valeriy Bardakov is a professor of Sobolev Institute of Mathematics with holding a joint position at Laboratory of Topology and Dynamics of Novosibirsk State University. Valeriy Bardakov is a famous expert on braid theory, knot theory and group theory with over 90 publications in the area.

Variational Bihamiltonian Cohomology and Integrable Hierarchie

Speaker：Youjin Zhang(Tsinghua University)

Time：2021.12.10 10:00-12:00

Location：Meeting Tencent

Meeting ID：924-966-280

Meeting：https://meeting.tencent.com/dm/4PgMu2SMQi39

Abstract: In order to study deformations of Virasoro symmetries of the bihamiltonian integrable hierarchies associated to semisimple Frobenius manifolds, we introduce the notion of variational bihamiltonian cohomology, and compute the cohomology groups that will be used in our study of deformations of Virasoro symmetries. To illustrate its application, we classify the conformal bihamiltonian structures with semisimple hydrodynamic limits.

O-operators on Lie infinity algebras

SpeakerJoana Nunes da Costa（University of Coimbra - Portugal）

Time：2021.12.03 16:00-18.00

Location：Zoom

ID：862 062 0549

Abstract: We define O-operators on a Lie infinity algebra E with respect to an action of E on another Lie infinity algebra. We characterize these operators as Maurer-Cartan elements of a certain Lie infinity algebra obtained by Voronov's higher derived brackets construction. We determine the Lie infinity algebra that controls the deformation of O-operators with respect to a fixed action.

Bio：Joana Nunes da Costa is a professor of University of Coimbra, Portugal. She mainly works on Poisson geometry and mathematical physics.

The Lang-Trotter Conjecture and the Hardy-Littlewood Conjecture

Speaker：Hourong Qin（Nanjing University）

Time：2021.11.26  09:00-11.00

Location：Meeting Tencent

Meeting ID：662 784 567

Bio： 秦厚荣教授现任南京大学数学系系主任，江苏国家应用数学中心主任，中国数学会常务理事，中国科学-数学编委，江苏省数学学会第十届，十一届理事长，第十二届监事会主席。1999年获得国家杰出青年基金，2004年受聘教育部长江学者计划特聘教授，首批入选国家“百千万人才计划”（2004年），享受国务院特殊津贴。他的研究方向主要是代数数论和代数K理论。他在同余数这一历史悠久问题上的研究上取得了重要成果；在数域的Tame核、Tate核方面做出了原创性工作，引发了大量后续工作；解决了田野，Browkin等人的多个猜想；在著名的椭圆曲线Anomalous素数的Mazur猜想以及Lang-Trotter猜想的研究中取得了突破。他在J. Reine Angew Math., P. London Math. Soc., Math. Ann. 等国际著名刊物上发表了数十篇论文，研究结果在国际同行中产生了广泛而积极的影响，被国外同行称为“秦的方法”，多次在高水平国际学术会议上作大会邀请报告。

Quantum GIM of N-fold affinization and quantum toroidal algebra

Speaker：Yun Gao（York University）

Time：2021.11.19  09:00-11.00

LocationZoom

Meeting ID：862 062 0549

Abstract: Generalized intersection matrix (GIM) Lie algebras were introduced by Slodowy in the study of elliptic singularity. GIM Lie algebras of N-fold affinization were studied by Berman-Moody, Benkart-Zelmanov and among others. In this talk we will talk about quantum GIM algebras of N-fold affinization and quantum toroidal algebras.

Bio： 郜云教授是加拿大York大学教授，德国洪堡学者。主要研究方向是无穷维李(超)代数、量子群和表示理论。在高维仿射李代数研究领域做出了重要工作。他已在国际一流数学杂志上发表论文50余篇，其中包括两本美国数学会专著(Memoirs of American athematical Society 1997和2002)。

Embedding of Loday algebras into Rota-Baxter algebras

SpeakerVsevolod Gubarev（Sobolev Institute of Mathematics，Novosibirsk State University）

Time：2021.11.12 15:00-17:00

LocationZoom

Meeting ID：862 062 0549

AbstractThe classical Poincare–Birkhoff–Witt states that every Lie algebra injectively embeds into its universal enveloping associative algebra and this enveloping algebra in some sense does not depend on the Lie product (PBW-property). It is known that every Rota–Baxter algebra of weight 0/1 gives rise to a prealgebra/postalgebra. In 2013, it was proved that every pre- or postalgebra injectively embeds into appropriate Rota–Baxter algebra of weight 0 or 1 respectively. We study the structure and the PBW-property of the universal enveloping Rota–Baxter algebra of a pre- and post-Lie algebra.

Bio：Vsevolod Gubarev ，Senior researcher in Sobolev Institute of Mathematics and senior teacher in Novosibirsk State University (both in Novosibirsk, Russia). Area of interest: ring theory.

Rota-Baxter operators and non-skew-symmetric solutions of the classical Yang-Baxter equation on quadratic Lie algebras

SpeakerMaxim Goncharov (Sobolev Institute of Mathematics，Novosibirsk State University)

Time：2021.11.5 15:00-17:00

LocationZoom

Meeting ID：862 062 0549

AbstractGiven a quadratic Lie algebra, it is well-known that skew-symmetric solutions of the classical Yang-Baxter equation are in one-to-one correspondence with skew-symmetric Rota-Baxter operators of weight zero. In this talk, we will study connections between Rota-Baxter operators of non-zero weight and non-skew-symmetric solutions of the classical Yang-Baxter equation on finite-dimensional quadratic Lie algebras. Particular attention will be given to the case of simple finite-dimensional Lie algebras.

Bio：Maxim Goncharov, Ph.D., Senior research fellow in Sobolev Institute of Mathematics, Associate Professor at Novosibirsk State University.

Revisiting and extending Poisson-Nijenhuis structures

SpeakerHenrique Bursztyn (Instituto Nacional de Matemática Pura e Aplicada)

Time：2021.10.22 08:00-09:00

Location：Zoom

Meeting ID：862 062 0549

AbstractPoisson-Nijenhuis structures arise in various contexts, such as the theory of integrable systems and Poisson-Lie theory. I will revisit this notion from a new perspective and show how it can be extended to the realm of Dirac structures. I also hope to mention applications to integration problems. The talk is based on joint work with T. Drummond and C. Netto.

Bio：Henrique Bursztyn is a professor of Instituto Nacional de Matemática Pura e Aplicada (IMPA), Brazil. His research interest includes Poisson geomety, Dirac structures, Lie groupoids, Lie algebroids, deformation quantization and mathematical physics. He published more than 70 papers in high level journals, such as Duke Math. J,  J. Reine Angew. Math.,  Compos. Math.,  Comm. Math. Phys.,  Int. Math. Res. Not. IMRN, Adv. Math.

Renormalization of quasisymmetric functions

SpeakerLi Guo (Rutgers University-Newark)

Time：2021.10.15 09:00

Location：Zoom

Meeting ID：862 062 0549

AbstractThe Hopf algebra of quasisymmetric functions (QSym) has played a central role in algebraic combinatorics and has broad applications. A natural linear basis of QSym is the set of monomial quasisymmetric functions defined by compositions, that is, vectors of positive integers. Extending such a definition for weak compositions, that is, vectors of nonnegative integers, leads to divergent expressions. This difficulty was addressed by a formal regularization in a previous work with Jean-Yves Thibon and Houyi Yu. Here we apply the method of renormalization in the spirit of Connes and Kreimer and realize weak composition quasisymmetric functions as power series. The resulting Hopf algebra has the Hopf algebra of quasisymmetric functions as both a Hopf subalgebra and a Hopf quotient algebra. It also gives a realization of free commutative Rota-Baxter algebra on one generator by weak quasisymmetric functions and thus addresses a question raise by Rota many years ago. This is a joint work with Houyi Yu and Bin Zhang.

Title：Koszul duality: old and new

Speaker：Andrey Lazarev(University of Lancaster)

Time：2021.10.8 15:00

Location：Zoom

Meeting ID：862 062 0549

AbstractKoszul duality is a phenomenon occurring in homological algebra and neighbouring fields, such as rational homotopy theory, representation theory, algebraic geometry, operads and operadic algebras. In this talk I will outline a modern approach to deformation theory based on Koszul duality and explain how it can be globalized.

Bio：Andrey Lazarev is a professor of pure mathematics in the University of Lancaster. His recent research deals with homotopy theory of differential graded algebras and categories, derived categories and higher phenomena. It has applications in rational homotopy theory, theory of operads and operadic algebras, algebraic topology and pure algebra. Andrey Lazarev is the Managing Editor of the journal《Bulletin of the London Mathematical Society》,as well as a Member of the Editorial Board of  the journal《Higher_Structures》.

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