| Weekday | Time | Venue | Online | ID | Password |
|---|---|---|---|---|---|
| Monday,Tuesday,Wednesday,Thursday,Friday,Saturday | 08:00 - 18:00 | Tsinghua University | - | - | - |
| Time\Date | Jan 1 Thu |
|---|---|
| 08:00-08:00 | Peter Sarnak |
| 08:00-18:00 | Xiangdong Ye |
*All time in this webpage refers to Beijing Time (GMT+8).
08:00-08:00 Peter Sarnak
On indefinite ternary quadratic forms
We describe the solution to two problems concerning indefinite integral ternary quadratic forms. The first about anisotropic forms was popularized by Margulis following his solution of the Oppenheim Conjecture. The second about the density of isotropic forms was raised by Serre. Joint work with A.Gamburd, A.Ghosh and J.Whang.
08:00-18:00 Xuemei Li
Coarse Curvature in Riemannian and Lorentzian Geometry
Einstein's field equations relate the curvature of spacetime to the distribution of matter and energy. Since Ollivier's influential work on Ricci curvature for Markov chains on metric spaces, there has been renewed interest in synthetic and coarse notions of curvature. In this talk, I shall discuss constructions of coarse curvature in both Riemannian and Lorentzian geometry. In the Riemannian setting, I shall describe coarse analogues of intrinsic Ricci curvature and of extrinsic curvature for embedded submanifolds. I shall then turn to the Lorentzian setting and discuss coarse notions of Ricci curvature associated with timelike directions.
08:00-18:00 Philippe Michel
08:00-18:00 Paul Bourgade
08:00-18:00 Yu Deng
08:00-18:00 Weixiao Shen
08:00-18:00 Benjamin Bedert
08:00-18:00 Emmanuel Breuillard
08:00-18:00 Jian Ding
08:00-18:00 Alexandra Florea
08:00-18:00 Shaoming Guo
08:00-18:00 Martin Hairer
08:00-18:00 Weikun He
08:00-18:00 Wen Huang
Typical periodic optimization for dynamical systems: Symbolic dynamics
This talk mainly reviews and introduces recent progress on the typical optimization of dynamical systems: the symbolic systems case. The contents include: the theory of maximizing sets in dynamical systems, for the study of ergodic optimization in systems with weak hyperbolicity, but where the Mañé cohomology lemma does not hold. The theory yields a structural theorem that isolates the part of the system responsible for any robust non-periodic optimization. The structural theorem is developed further in the setting of symbolic dynamics: given any shift space, for typical Lipschitz functons, the maximizing measure is shown to be either periodic or supported on the Markov boundary of the shift space. It follows that Contreras' Typical Periodic Optimization theorem for shifts of finite type can be extended to a wide class of shift spaces, including every sofic shift. This is joint work with Oliver Jenkinson, Leiye Xu, and Yiwei Zhang.
08:00-18:00 Lingfu Zhang
08:00-18:00 Jianya Liu
08:00-18:00 Péter Pál Pach
The Alon-Jaeger-Tarsi conjecture via group ring identities
The Alon-Jaeger-Tarsi conjecture states that for any finite field $\mathbb{F}$ of size at least 4 and any nonsingular matrix $A$ over $\mathbb{F}$ there exists a vector $x$ such that neither $x$ nor $Ax$ has a 0 component. In this talk we discuss the proof of this result for $|\mathbb{F}|>79$ and further applications of our method about coset covers and additive bases. Joint work with János Nagy and István Tomon.
08:00-18:00 Zeev Rudnick
Prime numbers, closed geodesics, and random hyperbolic surfaces
There is a close analogy between the theory of closed geodesics on a hyperbolic surface and prime number theory. This has been known since the 1950s. After surveying the two theories, I will discuss a recent perspective, when we consider the surface as being random in the moduli space of hyperbolic surfaces of large genus.
08:00-18:00 Damaris Schindler
08:00-18:00 Fernando Xuancheng Shao
08:00-18:00 Weijie Su
08:00-18:00 Xin Sun
08:00-18:00 Victor Wang
08:00-18:00 Ruodu Wang
08:00-18:00 Ping Xi
08:00-18:00 Lei Yang
08:00-18:00 Xiangdong Ye