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

On finite generation of the section ring of the determinant line bundle.

Speaker: 

Angela Gibney

Institution: 

University of Georgia

Time: 

Monday, November 7, 2016 - 3:00pm to 4:00pm

Host: 

Location: 

RH 306

I will discuss recent work, with Prakash Belkale, where we show the section ring for the pair (Bun, D) is finitely generated, for D the determinant of cohomology line bundle on the stack Bun = Bun_{SL(r)}(C) parameterizing principal SL(r)-bundles on a singular stable curve C.  I'll define these things, put the result into some historical perspective, and give two applications.

Dynamically distinguishing polynomials

Speaker: 

Derek Garton

Institution: 

Portland State University

Time: 

Tuesday, February 28, 2017 - 2:00pm to 3:00pm

Host: 

Location: 

RH 340P

Given two polynomials with integer coefficients, for how many primes p do the polynomials induce nonisomorphic dynamical systems mod p? This question will lead us to the study of the statistics of wreath products, the Galois theory of dynatomic polynomials, and other topics. This work is joint with Andrew Bridy.

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