学术报告
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Nonlinear Regression with Nonstationarity and HeteroscedasticityThis paper develops an asymptotic theory of nonlinear least squares estimation by establishing a new framework that can be easily applied to various nonlinear regression models with heteroscedasticity. This paper explores an application of the framework to nonlinear regression models with nonstationarity and heteroscedasticity. In addition to these main results, this paper provides a maximum inequality for a class of martingales and establishes some new results on convergence to a local time and convergence to a mixture of normal distributions.Professor Qiying Wang (澳大利亚,悉尼大学教授)致远楼101室2019年10月8日上午10:00
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Galerkin Solutions for Vanishing Delay Differential EquationsIn this report, we first introduce some backgrounds of delay differential equations and then consider the Galerkin method to solve the vanishing delay differential equations under uniform and quasi-graded mesh. The global convergence and local superconvergence results are obtained. Based on the local superconvergence results, several postprocessing techniques to accelerate the global convergence are proposed. State dependent delay differential equations are also considered. Theoretical expectations are confirmed by numerical experiments.黄秋梅 教授 (北京工业大学)宁静楼117室2019年9月27(周五) 16:00-17:00
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From the Centro-Affine Minkowski Problem to the Logarithmic Minkowski Inequal...We consider the logarithmic Minkowski inequality which is equivalent to several problems in convex geometric analysis and is still an open problem in dimension greater than 2. Among the problems equivalent to the logarithmic Minkowski inequality is the uniqueness of solutions to the logarithmic Minkowski problem. We present yet a new connection to a uniqueness of a Minkowski problem, namely if a given centro-affine Minkowski problem has unique solution (up to special linear group of transformations), then the corresponding logarithmic Minkowski inequality holds.Prof. Alina Stancu (Concordia University Canada)致远楼101室2019 年 09 月25 日 10:00-11:00
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Stochastic Symplectic Methods and Numerical Ergodicity of Stochastic Nonlinea...In this talk we present a review on stochastic symplecticity (multi-symplecticity) and ergodicity of numerical methods for stochastic nonlinear Schrödinger (NLS) equation. The equation considered is charge conservative and has the multi-symplectic conservation law. Based a stochastic version of variational principle, we show that the phase flow of the equation, considered as an evolution equation, preserves the symplectic structure of the phase space. We give some symplectic integrators and multi-symplectic methods for the equation. By constructing control system and invariant control set, it is proved that the symplectic integrator, based on the central difference scheme, possesses a unique invariant measure on the unit sphere.洪佳林 研究员(中国科学院 数学与系统科学研究院)致远楼101室2019年9月17日 16:00-17:00
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Variational Implicit-Solvent Predictions of the Dry–Wet Transition Pathways ...Ligand–receptor binding and unbinding are fundamental biomolecular processes and particularly essential to drug efficacy. Environmental water fluctuations, however, impact the corresponding thermodynamics and kinetics and thereby challenge theoretical descriptions. We devise a holistic, implicit-solvent, multi- method approach to predict the (un)binding kinetics for a generic ligand–pocket model. We use the variational implicit-solvent model (VISM) to calculate the solute–solvent interfacial structures and the corresponding free energies, and combine the VISM with the string method to obtain the minimum energy paths and transition states between the various metastable (“dry” and “wet”) hydration states.周圣高 副教授 (苏州大学)致远楼101室2019年9月9日 10:30-11:30
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Rigidity of Center Lyapunov Exponents and Su-IntegrabilityLet f be a conservative partially hyperbolic diffeomorphism which is homotopic to an Anosov automorphism A on T 3 . We show that the stable and unstable bundles of f are jointly integrable if and only if every periodic point of f admits the same center Lyapunov exponent with A. In particular, f is Anosov. This implies that every conservative partially hyperbolic diffeomorphism which is homotopic to an Anosov automorphism on T 3 is ergodic, which proves the Ergodic Conjecture proposed by Hertz-Hertz-Ures on T 3 . This is a joint work with Shaobo Gan.史逸 研究员(北京大学)宁静楼104室2019年8月28日11:00-12:00
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Some Progress on Studying Dynamical Systems beyond Uniform HyperbolicityThe study of Dynamical Systems is mainly concerned with orbit structure, specifically long term or asymptotic behavior, for maps or flows. Uniformly Hyperbolic systems are standard examples of complex or chaotic systems. However, uniformly hyperbolic systems are not dense in the space of all dynamical systems. After that people tried to know the world beyond uniform hyperbolicity for which there are many open questions proposed by Bowen, Palis etc. In this talk we will introduce some progress on Bowen's one question to search specification-like properties and statistical properties and Palis SRB conjecture to search the existence of SRB measures.田学廷 教授 (复旦大学)宁静楼104室2019年8月28日10:00-11:00
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Algebraic Birkhoff Factorization and Group Action in RenormalizationThe Algebraic Birkhoff Factorization (ABF) of Connes and Kreimer gives an algebraic formulation of the renormalization process in quantum field theory. Their ABF is an factorization of an algebra homomorphism from a Hopf algebra to a Rota-Baxter algebra. This algebraic formulation facilitates the mathematical study in renormalization and allows the renormalization method to be applied to problems in mathematics.Professor Li Guo (Rutgers University Newark)致远楼108室2019年8月26日 9:30-10:30