Seminars and Colloquia by Series

Concentration from Geometry in High Dimension: part 2

Series
High Dimensional Seminar
Time
Wednesday, September 12, 2018 - 12:55 for 1 hour (actually 50 minutes)
Location
Skiles 006
Speaker
Santosh VempalaGeorgia Institute of technology

The concentration of Lipschitz functions around their expectation is a classical topic and continues to be very active. In these talks, we will discuss some recent progress in detail, including: A tight log-Sobolev inequality for isotropic logconcave densities A unified and improved large deviation inequality for convex bodies An extension of the above to Lipschitz functions (generalizing the Euclidean squared distance)The main technique of proof is a simple iteration (equivalently, a Martingale process) that gradually transforms any density into one with a Gaussian factor, for which isoperimetric inequalities are considerably easier to establish. (Warning: the talk will involve elementary calculus on the board, sometimes at an excruciatingly slow pace). Joint work with Yin Tat Lee.

Concentration from Geometry in High Dimension

Series
High Dimensional Seminar
Time
Wednesday, September 5, 2018 - 12:55 for 1 hour (actually 50 minutes)
Location
Skiles 006
Speaker
Santosh VempalaGeorgia Institute of Technology

The concentration of Lipschitz functions around their expectation is a classical topic and continues to be very active. In these talks, we will discuss some recent progress in detail, including: A tight log-Sobolev inequality for isotropic logconcave densities A unified and improved large deviation inequality for convex bodies An extension of the above to Lipschitz functions (generalizing the Euclidean squared distance)The main technique of proof is a simple iteration (equivalently, a Martingale process) that gradually transforms any density into one with a Gaussian factor, for which isoperimetric inequalities are considerably easier to establish. (Warning: the talk will involve elementary calculus on the board, sometimes at an excruciatingly slow pace). Joint work with Yin Tat Lee.

Banach--Mazur distance to the cube

Series
High Dimensional Seminar
Time
Wednesday, August 29, 2018 - 12:55 for 1 hour (actually 50 minutes)
Location
Skiles 006
Speaker
Konstantin TikhomirovGeorgiaTech

We show that there is a symmetric n-dimensional convex set whose Banach--Mazur distance to the cube is bounded below by n^{5/9}/polylog(n). This improves previously know estimate due to S.Szarek, and confirms a conjecture of A.Naor. The proof is based on probabilistic arguments.

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