Upcoming Seminars & Events

Subscribe to Seminars & Events
October 20, 2014
4:30pm - 5:30pm
Exact post-selection inference

This is a joint PACM/ORFE Colloquium:  We describe a framework for exact post-selection inference.At the core of our framework is what we call selective inferencewhich allows us to define selective Type I and II errors for hypothesis tests and selective coverage for intervals.  Several examples are discussed including the LASSO, forward stepwise, change point detection.  This is joint work with several: Will Fithian, Jason Lee, Richard Lockart, Joshua Loftus, Dennis Sun, Yuekai Sun, Ryan Tibshirani, Rob Tibshirani.

Speaker: Jonathan Taylor , Stanford University
Location:
Fine Hall 214
October 21, 2014
3:00pm - 4:00pm
Special PACM Seminar: Critical points and integral geometry of smooth Gaussian random functions

Please note special day, time and location.  In this survey talk, we describe some what might be described as the geometric theory of smooth (marginally stationary) Gaussian random functions. Beginning at the local level, the celebrated Kac-Rice formulacan be used to derive accurate approximations to the distribution of the maximum of such random functions. From this local calculation,global Riemannian integral invariants appear. Zooming out to a global level,the appearance of these integral invariants can be explained by appealing to the Kinematic Fundamental Formula.  Time permitting, we describe recent applications of the Kac-Rice formula high-dimensional statistical inference:http://arxiv.org/abs/1308.3020.These applications demonstrate the promise this local tool holds for inference about critical points for random fields that are not marginally stationary.

Speaker: Jonathan Taylor , Stanford University
Location:
Fine Hall 110
October 22, 2014
4:30pm - 5:30pm
Branching laws and period integrals for non-tempered representations

Question about decomposition of representations of groups over local fields to subgroups, such as from SO(n) to SO(n-1), has been of considerable interest in the recent past with impressive works of Waldspurger, Moeglin-Waldspurger, and Raphael Beuzart-Plessis. Corresponding global question for unitary groups has been partly settled by Wei Zhang. These questions have so far been considered only for tempered representations (of the group and the subgroup). In this lecture, I will discuss the situation with non-tempered representations with many examples.

Speaker: Dipendra Prasad, Tata Institute of Fundamental Research, Mumbai, India
Location:
Fine Hall 314
October 23, 2014
2:00pm - 3:30pm
Burgers equation with random forcing

The Burgers equation is one of the basic nonlinear evolutionary PDEs. The study of ergodic properties of the Burgers equation with random forcing began in 1990's. The natural approach is based on the analysis of optimal paths in the random landscape generated by the random force potential. For a long time only compact cases of the Burgers dynamics on a circle or bounded interval were understood well. In this talk I will discuss the Burgers dynamics on the entire real line with no compactness or periodicity assumption on the random forcing. The main result is the description of the ergodic components and existence of a global attracting random solution in each component. The proof is based on ideas from the theory of first or last passage percolation. My new work on kicked forcing is an extension of joint work with Eric Cator and Kostya Khanin on Poissonian forcing. 

Speaker: Yuri Bakhtin , Courant Institute of Mathematical Sciences, New York University
Location:
Fine Hall 601
October 23, 2014
3:00pm - 4:00pm
Stein's conjecture and other fair representation problems

Stein's conjecture states that if an n x n matrix has entries 1...n, where each symbol appears exactly n times, then there exists a generalized diagonal where all but two symbols appear exactly once. I will talk about this conjecture and other settings in which we look for a small structure proportionally representing the bigger structure from which it is taken. 

Speaker: Eli Berger , Haifa University
Location:
Fine Hall 224
October 23, 2014
3:00pm - 4:00pm
On the topological complexity of 2-torsion lens spaces

The topological complexity of a topological space is the minimum number of rules required to specify how to move between any two points of the space. A ``rule'' must satisfy the requirement that the path varies continuously with the choice of end points. We use connective complex K-theory to obtain new lower bounds for the topological complexity of 2-torsion lens spaces. We follow a program set up by Jesus Gonzalez, and answer a question posed by him.

Speaker: Don Davis , Lehigh University
Location:
Fine Hall 314
October 23, 2014
4:30pm - 5:30pm
TBA - Candelori
Speaker: Luca Candelori , LSU
Location:
IAS Room S-101
October 24, 2014
11:00am - 12:00pm
Joint Columbia-IAS-Princeton Symplectic Seminar: Symplectic embeddings from concave toric domains into convex ones

This is a Joint Columbia-IAS-Princeton Symplectic Seminar. Embedded contact homology gives a sequence of obstructions to four-dimensional symplectic embeddings, called ECH capacities. These obstructions are known to be sharp in several interesting cases, for example for symplectic embeddings of one ellipsoid into another. We explain why ECH capacities give a sharp obstruction to embedding any "concave toric domain" into a "convex" one. We also explain why the ECH capacities of any concave or convex toric domain are determined by the ECH capacities of a corresponding collection of balls. Some of this is joint work with Keon Choi, David Frenkel, Michael Hutchings, and Vinicius Ramos.

Speaker: Dan Cristofaro-Gardiner , Harvard University
Location:
IAS Room S-101
October 24, 2014
1:30pm - 2:30pm
Joint Columbia-IAS-Princeton Symplectic Seminar: Beyond ECH capacities

This is a Joint Columbia-IAS-Princeton Symplectic Seminar.   ECH (embedded contact homology) capacities give obstructions to symplectically embedding one four-dimensional symplectic manifold with boundary into another. These obstructions are known to be sharp when the domain is a "concave toric domain" and the target is a "convex toric domain” (see previous talk). However ECH capacities often do not give sharp obstructions, for example in many cases when the domain is a polydisk. In this talk we explain how more refined information from ECH gives stronger symplectic embedding obstructions when the domain is a polydisk, or more generally a convex toric domain. We use these new obstructions to reprove a result of Hind-Lisi on symplectic embeddings of a polydisk into a ball, and generalize this to obstruct some symplectic embeddings of a polydisk into an ellipsoid. We also obtain a new obstruction to symplectically embedding one polydisk into another, in particular proving the four-dimensional case of a conjecture of Schlenk.

Speaker: Michael Hutchings , UC Berkeley
Location:
IAS Room S-101
October 31, 2014
1:30pm - 2:30pm
On the Gromov width of polygon spaces

After Gromov’s foundational work in 1985, problems of symplectic embeddings lie in the heart of symplectic geometry. The Gromov width of a symplectic manifold \((M, \omega)\) is a symplectic invariant that measures, roughly speaking, the size of the biggest ball we can symplectically embed in \((M, \omega)\). I will discuss tecniques to compute the Gromov width of a special family of symplectic manifolds, the moduli spaces of polygons in \(\mathbb{R}^3\) with edges of lengths \((r_1,\ldots, r_n)\). Under some genericity assumptions on lengths \(r_i\), the polygon space is a symplectic manifold. After introducing this family of manifolds, I will concentrate on the spaces of 5-gons and calculate their Gromov width. This is joint work with Milena Pabiniak, IST Lisbon.

Speaker: Alessia Mandini , University of Pavia
Location:
Fine Hall 322
November 3, 2014
3:15pm - 4:30pm
Decouplings and applications

We describe a new Fourier analytic method for estimating a wide variety of exponential sums. The talk will mainly focus on  the applications to number theory and PDEs. This is joint work  with Jean Bourgain. 

Speaker: Ciprian Demeter , Indiana University
Location:
Fine Hall 314
November 3, 2014
4:30pm - 5:30pm
Set Oriented Numerical Methods for Dynamical Systems and Optimization

Over the last two decades so-called set oriented numerical methods have been developed in the context of the numerical treatment of dynamical systems. The basic idea is to cover the objects of interest - for instance invariant sets or invariant measures - by outer approximations which are created via multilevel subdivision techniques. At the beginning of this century these methods have been modified in such a way that they are also applicable to the numerical treatment of multiobjective optimization problems. Due to the fact that they are set oriented in nature these techniques allow for the direct computation of the entire so-called Pareto set.  In this talk recent developments in the area of set oriented numerics will be presented both for dynamical systems and optimization problems. The reliability of these methods will be demonstrated by several applications such as the approximation of transport processes in ocean dynamics, or the optimization of a cruise control with respect to energy consumption and travel distance. Moreover a new algorithmic idea will be described which allows to compute invariant sets directly by Newton's method.

Speaker: Michael Dellnitz , University of Paderborn, Germany
Location:
Fine Hall 214
November 6, 2014
3:00pm - 4:00pm
TBA - Holm
Speaker: Tara Holm , Cornell and the IAS
Location:
Fine Hall 314
November 6, 2014
4:30pm - 5:30pm
TBA - Hou
Speaker: Yong Hou, Zanty Electronics
Location:
Fine Hall 314
November 6, 2014
4:30pm - 6:00pm
Thin knotted vortex tubes in stationary solutions to the Euler equation

In this talk we will discuss the proof of the existence of thin vortex tubes for stationary solutions to the incompressible Euler equation in R^3. More precisely, given a finite collection of (possibly linked and knotted) disjoint thin tubes in R^3, we will show that they can be transformed using a small diffeomorphism into a set of vortex tubes of a Beltrami field that tends to zero at infinity.

 

Speaker: Alberto Enciso, ICMAT - Madrid
Location:
Fine Hall 322
November 6, 2014
4:30pm - 5:30pm
TBA - Tiep
Speaker: Pham Tiep , Harvard University / University of Arizona
Location:
IAS Room S-101
November 7, 2014
1:30pm - 2:30pm
TBA - Müller
Speaker: Stefan Müller , UIUC
Location:
IAS Room S-101
November 7, 2014
3:00pm - 4:00pm
TBA - Lee
Speaker: John Lee, University of Washington, Seattle
Location:
Fine Hall 314
November 7, 2014
4:15pm - 5:15pm
TBA - Chodosh
Speaker: Ottis Chodosh, Stanford University
Location:
Fine Hall 314
November 10, 2014
3:15pm - 4:30pm
TBA - Nahmod
Speaker: Andrea Nahmod, University of Massachusetts Amherst
Location:
Fine Hall 314

Pages