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Monday, 9 October  

Time  Speaker  标题  Location 
15:00  16:00  Nihar Gargava EPFL 
Abstract
In 1945, Siegel showed that the expected value of the latticesums of a function over all the lattices of unit covolume in an ndimensional real vector space is equal to the integral of the function. In 2012, Venkatesh restricted the latticesum function to a collection of lattices that had a cyclic group of symmetries and proved a similar mean value theorem. Using this approach, new lower bounds on the most optimal sphere packing density in n dimensions were established for infinitely many n. In the talk, we will outline some analogues of Siegel's mean value theorem over lattices. This approach has modestly improved some of the best known lattice packing bounds in many dimensions. We will speak of some variations and related ideas. (Joint work with V. Serban, M. Viazovska)
Ergodic theory and dynamical systems seminar
Random Arithmetic Lattices as Sphere Packingsread_more 
Y27H 25 
15:00  16:30  Dr. Yalong Cao RIKEN (Japan) 
Abstract
抖抖与势的基本对象geometric representation theory and important also in DonaldsonThomas theory of CalabiYau 3categories. In this talk, we will introduce quantum corrections to such objects by counting quasimaps from curves to the critical locus of the potential. Our construction is based on the theory of gauged linear sigma model (GLSM) and uses recent development of DT theory of CY 4folds. Joint work with Gufang Zhao.
Algebraic Geometry and Moduli Seminar
Quasimaps to quivers with potentialsread_more 
ITS 
15:15  16:10  Fabian Ziltener ETH 
Abstract
This talk is about joint work with Yann Guggisberg. The main result is that the set of generalized symplectic capacities is a complete invariant for every symplectic category whose objects are of the form $(M,\omega)$, such that $M$ is compact and 1connected, $\omega$ is exact, and there exists a boundary component of $M$ with negative helicity. This answers a question of Cieliebak, Hofer, Latschev, and Schlenk. It appears to be the first result concerning this question, except for results for manifolds of dimension 2, ellipsoids, and polydiscs in $\mathbb{R}^4$. If time permits, then I will also present some answers to the following question and problem of Cieliebak, Hofer, Latschev, and Schlenk: Question: Which symplectic capacities are connectedly targetrepresentable? Problem: Find a minimal generating set of symplectic capacities.
Symplectic Geometry Seminar
Capacities as a complete symplectic invariantread_more 
HG G 43 
16:25  17:20  Valentin Bosshard ETH 
Abstract
Lagrangian cobordisms induce exact triangles in the Fukaya category. But how many exact triangles can be recovered by Lagrangian cobordisms? One way to measure this is by comparing the Lagrangian cobordism group to the Grothendieck group of the Fukaya category. In this talk, we discuss the setting of exact conical Lagrangian submanifolds in Liouville manifolds and compute Lagrangian cobordism groups of Weinstein manifolds. As an application, we get a geometric interpretation for Viterbo restriction for Lagrangian cobordism groups.
Symplectic Geometry Seminar
The Lagrangian cobordism group of Weinstein manifoldsread_more 
HG G 43 
Tuesday, 10 October  

Time  Speaker  标题  Location 
10:30  12:00  Xenia Flamm Examiner: Prof. Dr. Marc Burger 
HG D 16.2 
Wednesday, 11 October  

Time  Speaker  标题  Location 
13:30  15:00  Dr. Johannes Schmitt ETH Zürich 
Abstract
Given a smooth algebraic variety (or orbifold) X with a normal crossings divisor D, the space X decomposes into strata describing the loci where various components of D (self)intersect. In this series of four lectures, we will study the intersection theory of X, as well as certain birational modifications of X obtained by iteratively blowing up some of the strata. In recent years, the logarithmic Chow ring of the pair (X,D) was defined to encode the intersection theory of all such iterated blowups simultaneously. This allows to perform calculations with strict transforms of cycles on X without specifying a concrete birational model of X in which they live, and has been applied successfully in studying certain geometric cycles on moduli spaces. In the first lecture, we give an overview of the relevant definitions, a sketch of some of their applications, and a roadmap for the following talks. The second lecture talks about the case where X is a toric variety (and D its toric boundary), and explains that here the entire intersection theory is described in terms of convex geometric data (the fan Sigma of X and piecewise polynomial functions on Sigma). Then we show how the language of cone stacks and Artin fans can be used to generalize from the toric situation to arbitrary pairs (X,D). Finally, we talk about ongoing work on the logarithmic Chow ring of the moduli space of curves.
Algebraic Geometry and Moduli Seminar
Log intersection theory: from toric varieties to moduli of curves Iread_more 
HG G 43 
16:30  17:30  Dr. Théophile ChaumontFrelet Inria 
Abstract
Timeharmonic Maxwell's equations model the propagation of electromagnetic waves, and their numerical discretization by finite elements is instrumental in a large array of applications. In the simpler setting of acoustic waves, it is known that (i) the Galerkin Lagrange finite element approximation to a Helmholtz problem becomes asymptotically optimal as the mesh is refined. Similarly, (ii) asymptotically constantfree a posteriori error estimates are available for Helmholtz problems. In this talk, considering Nédélec finite element discretizations of timeharmonic Maxwell's equations, I will show that (i) still holds true and propose an a posteriori error estimator providing (ii). Both results appear to be novel contributions to the existing literature.
Zurich Colloquium in Applied and Computational Mathematics
Asymptotically optimal a priori and a posteriori error estimates for edge finite element discretizations of timeharmonic Maxwell's equationsread_more 
HG E 1.2 
17:15  18:45  Prof. Dr. Aleksandar Mijatovic University of Warwick 
Abstract
In this talk we quantify the asymptotic behaviour of multidimensional drifltess diffusions in domains unbounded in a single direction, with asymptotically normal reflections from the boundary. We identify the critical growth/contraction rates of the domain that separate stability, null recurrence and transience. In the stable case we prove existence and uniqueness of the invariant distribution and establish the polynomial rate of decay of its tail. We also establish matching polynomial upper and lower bounds on the rate of convergence to stationarity in total variation. All exponents are explicit in the model parameters that determine the asymptotics of the growth rate of the domain, the interior covariance, and the reflection vector field. Proofs are probabilistic, and use upper and lower tail bounds for additive functionals up to return times to compact sets, for which we develop novel sub/supermartingale criteria, applicable to general continuous semimartingales. Time permitting, I will discuss the main ideas behind the proofs in the talk. This is joint work with Miha Bresar (Warwick) and Andrew Wade (Durham).
Seminar on Stochastic Processes
Brownian motion with asymptotically normal reflection in unbounded domains: from transience to stabilityread_more 
Y27H12 
Thursday, 12 October  

Time  Speaker  标题  Location 
15:00  16:00  Paula Truölcall_made MPIM Bonn 
Abstract
Algebraic geometry studies solution sets of polynomial equations in multiple variables. For example, an algebraic plane curve is the zero set of a polynomial in two (say, complex) variables. Knot theory, on the other hand, studies 1dimensional submanifolds of the 3sphere from a topological perspective  up to continuous deformations. How are these two areas of mathematics related? We will draw connections between knot theory and the study of singularities of algebraic plane curves, assuming no knowledge of either area.
Geometry Graduate Colloquium
Relating knot theory to algebraic geometryread_more 
HG G 19.1 
17:15  18:15  Prof. Dr. Benjamin Jourdaincall_made CERMICS 
Abstract
We consider driftless onedimensional stochastic differential equations. We first recall how they propagate convexity at the level of single marginals. We show that some spatial convexity of the diffusion coefficient is needed to obtain more general convexity propagation and obtain functional convexity propagation under a slight reinforcement of this necessary condition. Such conditions are not needed for directional convexity.
Talks in Financial and Insurance Mathematics
凸性和凸或传播dering of onedimensional stochastic differential equationsread_more 
HG G 43 
Friday, 13 October  

Time  Speaker  标题  Location 
14:15  15:15  博士教授威廉公爵 UCLA 
HG G 43 

16:00  17:30  Dr. Fatemeh Rezaee Cambridge and ETHZ 
Abstract
Let X be a smooth projective variety. Define a stable map f : C → X to be eventually smoothable if there is an embedding X → PN such that (C,f) occurs as the limit of a 1parameter family of stable maps to PN with smooth domain curves. Via an explicit deformationtheoretic construction, we produce a large class of stable maps (called stable maps with model ghosts), and show that they are eventually smoothable. This is joint work with Mohan Swaminathan.
Algebraic Geometry and Moduli Seminar
Constructing smoothings of stable mapsread_more 
HG G 43 