# 2010 2011 Dispersive PDE Seminar

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This page contains information about an informal seminar on Dispersive PDEs during 2009-2010. The seminar is organized by J. Colliander and M. Czubak.

Of related interest in Toronto (and sometimes cross-listed):

Archives:

## June 22, Richards, 11:10-12:00 @BA 6183

 Geordie Richards (University of Toronto) Dispersive_PDE_Seminar Wednesday June 22 11:10-12:00 BA 6183 Title: Function spaces for critical well-posedness theory Abstract: We will introduce the (closely related) function spaces of $U^p$ and $V^p$ type, due to Koch-Tataru ($U^p$) and Wiener ($V^p$), which can be useful in the analysis of nonlinear dispersive PDEs at critical regularity. Time permitting, we will discuss the proof of local well-posedness of the Cauchy problem for the Kadomtsev-Petviashvili-II (KP-II) equation in a critical space, and highlight the role played by a nonlinear estimate in the $U^p, V^p$ spaces. [HHK 2009] M. Hadac, S. Herr, H. Koch, Well-posedness and scattering for the KP-II equation in a critical space. arXiv:0708.2011 arXiv 2011_06_22_Richards_Notes 2011_06_22

## November 30, Wang, 1:30-3:00 @KP 113

 Jing Wang (University of Toronto) Dispersive_PDE_Seminar Tuesday November 30 1:30-3:00 KP 113 Title: Bilinear estimates and applications to NLW Abstract: We will continue the paper of Klainerman and Selberg.This time, we prove local wellposedness for the wave map type equations by the Picard iteration.The nonlinear estimates we have proved last time play an important role. [{{{arxiv}}} arXiv] 2010_11_30_Wang_Notes 2010_11_30

## November 16, Colliander, 1:30-3:00 @KP 113

 James Colliander [1] (University of Toronto) Dispersive_PDE_Seminar Tuesday November 16 1:30-3:00 KP 113 Title: Critical Element + Rigidity Strategy for Evolution PDEs Abstract: A robust strategy for studying the maximal-in-time behavior of evolution PDEs has emerged in the past decade. The strategy has led to definitive progress on certain nonlinear Schrödinger equations, nonlinear wave equations and recently on the Navier-Stokes system. This talk will describe some aspects of this strategy. [{{{arxiv}}} arXiv] 2010_11_16_Colliander_Notes 2010_11_16

## November 09, Wang, 1:30-3:00 @KP 113

 Jing Wang (University of Toronto) Dispersive_PDE_Seminar Tuesday November 09 1:30-3:00 KP 113 Title: Bilinear estimates and applications to NLW Abstract: I will give a short introduction to the paper of Klainerman and Selburg: Bilinear estimates and applications to nonlinear wave equations. In this paper, Klainerman and Selburg considered the Cauchy problem for three types nonlinear wave equations. They construct the so called wave sobolev space to get the local wellposedness. We will focus on this space and the related estimates since the method to prove local wellposedness is standard. In fact, the wave sobolev space is the Bourgain space in the wave equation context. As the Bourgain space corresponding Schrodinger equation is well known, we will see there are similar properties between the two spaces. [{{{arxiv}}} arXiv] 2010_11_09_Wang_Notes 2010_11_09

## November 02, Huang, 1:30-3:00 @KP 113

 Arthur Huang (University of Toronto) Dispersive_PDE_Seminar Tuesday November 02 1:30-3:00 KP 113 Title: Refinement of the Strichartz's inequality for non-elliptic Fourier restriction Abstract: (Continued from 19 October...) Among the several refinements of Strichartz's inequality, the type bounding the L^4-norm in space-time of the free evolution by the X^p-norm (1

## October 19, Huang, 1:30-3:00 @KP 113

 Arthur Huang (University of Toronto) Dispersive_PDE_Seminar Tuesday October 19 1:30-3:00 KP 113 Title: Refinement of the Strichartz's inequality for non-elliptic Fourier restriction Abstract: Among the several refinements of Strichartz's inequality, the type bounding the L^4-norm in space-time of the free evolution by the X^p-norm (1

## October 12, Pigott, 1:30-3:00 @KP 113

 Brian Pigott (University of Toronto) Dispersive_PDE_Seminar Tuesday October 12 1:30-3:00 KP 113 Title: Upper bounds on the orbital instability of the generalized KdV equations below the energy norm Abstract: In this talk I will discuss some of the details relevant in establishing polynomial-in-time upper bounds on the orbital instability of the generalized KdV equations below H^1. The talk will focus on the construction of an almost conserved quantity which can be used to establish these upper bounds. [{{{arxiv}}} arXiv] 2010_10_12_Pigott_Notes 2010_10_12

## October 5, Richards, 1:30-3:00 @KP 113

 Geordie Richards (University of Toronto) Dispersive_PDE_Seminar Tuesday October 5 1:30-3:00 KP 113 Title: Invariant Gibbs measures for periodic nonlinear Schrodinger equations, Part II Abstract: This talk is a continuation of the FAWG talk from last week. Last week, we discussed two papers of Bourgain [MR1309539 (95k:35185), MR1374420 (96m:35292)] on the invariance of (suitably normalized) Gibbs measures under the flow of some periodic nonlinear Schrodinger (NLS) equations. In this second talk, we will focus on Bourgains second paper, where he proves that the Wick-ordered Gibbs measure is invariant under the flow of the Wick-ordered 2-dimensional cubic NLS. Bourgain's proof of almost sure LWP in the support of the Wick-ordered Gibbs measure (an ingredient in the proof of the Gibbs measure invariance) combines techniques from dispersive PDE and probability theory; he establishes an effect of nonlinear smoothing under randomization of the initial data. We will discuss this LWP argument. [{{{arxiv}}} arXiv] 2010_10_5_Richards_Notes 2010_10_5