Noncommutative Majorization Principles and Grothendieck's Inequality

Speaker: 

Steven Heilman

Institution: 

UCLA

Time: 

Tuesday, November 29, 2016 - 11:00pm to 11:50pm

Host: 

Location: 

RH 306

The seminal invariance principle of Mossel-O'Donnell-Oleszkiewicz implies the following. Suppose we have a multilinear polynomial Q, all of whose partial derivatives are small. Then the distribution of Q on i.i.d. uniform {-1,1} inputs is close to the distribution of Q on i.i.d. standard Gaussian inputs. The case that Q is a linear function recovers the Berry-Esseen Central Limit Theorem. In this way, the invariance principle is a nonlinear version of the Central Limit Theorem. We prove the following version of one of the two inequalities of the invariance principle, which we call a majorization principle. Suppose we have a multilinear polynomial Q with matrix coefficients, all of whose partial derivatives are small. Then, for any even K>1, the Kth moment of Q on i.i.d. uniform {-1,1} inputs is larger than the Kth moment of Q on (carefully chosen) random matrix inputs, minus a small number. The exact statement must be phrased carefully in order to avoid being false. Time permitting, we discuss applications of this result to anti-concentration, and to computational hardness for the noncommutative Grothendieck inequality. (joint with Thomas Vidick) (

Open problems in Mean Field Games theory

Speaker: 

Wilfrid Gangbo

Institution: 

UCLA

Time: 

Thursday, January 26, 2017 - 4:00pm to 5:00pm

Host: 

Location: 

RH306

We present some of the recent results in Mean Field Games theory, especially the so–called master equation, backbone of the MFG the- ory. Despite the fact that the master equation is a non–local first order equation, we show how it is linked to metric viscosity solutions of a local Hamilton–Jacobi equation on the set of probability measures. (This talk is based on a joint work with A. Swiech). 

Invariants in the Bergman and Szeg\H o kernels in strictly pseudoconvex domains in $\mathbb C^2$

Speaker: 

Peter Ebenfelt

Institution: 

UCSD

Time: 

Thursday, November 17, 2016 - 4:00pm to 5:00pm

Host: 

Location: 

RH 306

 The Bergman and Szeg\H o kernels in a bounded domain $\Omega\subset \mathbb C^n$ are the reproducing kernels for the holomorphic functions in $L^2(\Omega,dV)$ and $L^2(\partial \Omega,d\sigma)$, respectively, where $dV$ denotes the standard Lebesgue measure in $\bC^n$ and $d\sigma$ a surface measure on the boundary $\partial\Omega$. Their restrictions to the diagonal are known to have asymptotic expansions of the form:

$$K_B\sim \frac{\phi_B}{\rho^{n+1}}+\psi_B\log\rho,\quad K_S\sim \frac{\phi_S}{\rho^{n}}+\psi_S\log\rho,$$

where $\phi_B,\phi_S,\psi_B,\psi_S\in C^\infty(\overline{\Omega})$ and $\rho>0$ is a defining equation for $\Omega$. The functions $\phi_B,\phi_S,\psi_B,\psi_S$ encode a wealth of information about the biholomorphic geometry of $\Omega$ and its boundary $\partial \Omega$. In this talk, we will discuss this in the context of bounded strictly pseudoconvex domains in $\mathbb C^2$ and pay special attention to the lowest order invariants in the log term and a strong form of a conjecture of Ramadanov.

Boundedness for the General Semilinear Duffing Equations via the Twist Theorem

Speaker: 

Daxiong Piao

Institution: 

Ocean University, China

Time: 

Thursday, September 8, 2016 - 2:00pm

Location: 

RH 340P

We consider the boundedness of all solutions for the periodic semilinear equation where the non-linear term does not necessarily satisfy the so called polynomial-like growth condition. Usually this condition is needed in the references about boundedness problems of semilinear Duffing equations. Two cases of resonance and non-resonance are considered respectively.

 

* Joint work with Yiqian Wang, Zhiguo Wang, Lei Jiao and Xiao Ma

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