学术报告
-
Local Bilinear Controllability of the Schrödinger EquationWe will present the problem of bilinear controllability for Schrödinger equation in a bounded domain, i.e the possibility of controlling the equation by an action on a potential, with the difficulties and the few available results and methods up to now. We will then present a new result of local bilinear controllability in dimension 3 in a neighborhood of an eigenfunction corresponding to a simple eigenvalue and with a non-degeneracy condition of the normal derivative on a part of the boundary satisfying the geometric control condition.Jean-Pierre Puel致远楼101室2018年6月29日 上午10:00
-
Recent Progress on DDVV-Type InequalitiesRecently, we generalize the known DDVV-type inequalities for real (skew-)symmetric and complex (skew-)Hermitian matrices into arbitrary real, complex and quaternionic matrices. Inspired by the Erd/H{o}s-Mordell inequality, we establish DDVV-type inequalities for matrices in the subspaces spanned by a Clifford system or a Clifford algebra. We also generalize the B/"{o}ttcher-Wenzel inequality to quaternionic matrices. In this talk, we will briefly introduce the background, the new progress above, and some open questions.葛建全致远楼 103 室2018 年 06 月27 日 16:00-17:00
-
Rigidity of Einstein Four-Manifolds with Positive Sectional CurvatureEinstein metrics are natural Riemannian metrics on differentiable manifolds. In dimensions 2 and 3, they must have constant sectional curvature, while in dimension 4, they are much more complicated. For the complex setting, in 1990 Tian classified Kahler-Einstein four-manifolds with positive scalar curvature, and in 2012 LeBrun classified Hermitian, Einstein four-manifolds with positive scalar curvature. For the real setting, however less is known, even assuming a (strong) condition of positive sectional curvature.吴鹏致远楼 103 室2018 年 06 月27 日 14:30-15:30
-
SLLN for the Sequence of Maximum of Partial SumsLet ,let be a sequence of independent copies of a real-valued random variable , and set , . Motivated by a Theorem of Mikosch (1984), this talk is devoted to establishing a strong law of large numbers for the sequence . More specifically, necessary and sufficient conditions are given for whereProfessor Deli Li致远楼101室2018年6月25日(周一)上午10:00
-
Optimal Coverage Control of Heterogeneous Mobile Sensor NetworksThe coverage control problem of a network of heterogeneous mobile sensors is addressed in this talk, where the goal is to minimize a coverage cost function which is defined to be the largest arrival time from the mobile sensor network to the points on a cricle. A necessary and sufficient condition for the global minimization of the coverage cost function is firstly derived. Then, distributed coverage control schemes with input saturation are developed to drive the sensors to the optimal configuration such that the necessary and sufficient condition is satisfied. Under the distributed coverage control schemes, the mobile sensors’ spatial order on the circle is preserved throughout the network’s evolution and thus collision between mobile sensors is avoided. Finally, simulation results are presented to illustrate the effectiveness of the proposed distributed control schemes.Gang Feng致远楼103室2018年6月25日(周一) 16:15
-
Hadamard Variational Formulas for Two Functionals and its Application to Rela...In this paper, we pose two kinds of Minkowski problems involving the $p$-Laplacian operator. The Hadamard variational formulas for some $p$-Laplacian functionals are obtained. A good application is to prove symmetry results for solutions to some overdetermined problems of $p$-Laplacian equations.徐露致远楼101室2018 年 06 月22 日 15:00-16:00
-
T-duality in an H-Flux and Exotic Twisted Equivariant Cohomology TheoriesT-duality is an equivalence of two physical theories (quantum field theories or string theories) with different spacetime geometries. It originates from string theories, finds applications in condensed matter physics and has profound connections with topology/geometry. In this talk, I will first briefly review the elegant mathematical formulation of T-duality in an H-flux by Bouwknegt-Evslin-Mathai. Then I will describe our joint work with Mathai about developing exotic twisted /mathbb{T}-equivariant cohomology theories in order to enhance the T-duality by capturing the exchange of winding and momentum, a fundamental feature of T-duality.韩飞 教授致远楼101室2018年6月21日 16:00-17:00
-
Singular Constant Scalar Curvature Kahler MetricsI would present the recent progress in the construction of singular constant scalar curvature Kahler (cscK) metrics. The singular cscK metric is an extension of the singular Kahler-Einstein metric.I would also present the application of such singular metrics to Yau-Tian-Donaldson conjecture.郑恺 博士致远楼101室6月21日(周四)15:00-16:00