Date:

Tue, 24/11/201514:00-15:00

Location:

Manchester building, Hebrew University of Jerusalem, (Room 209)

The Danzer problem and a solution to a related problem of Gowers

Is there a point set Y in R^d, and C>0, such that every convex

set of volume 1 contains at least one point of Y and at most C? This

discrete geometry problem was posed by Gowers in 2000, and it is a special

case of an open problem posed by Danzer in 1965. I will present two proofs

that answers Gowers' question with a NO. The first approach is dynamical;

we introduce a dynamical system and classify its minimal subsystems. This

classification in particular yields the negative answer to Gowers'

question. The second proof is direct and it has nice applications in

combinatorics. The talk will be accessible to a general audience. [This is

a joint work with Omri Solan and Barak Weiss].

Is there a point set Y in R^d, and C>0, such that every convex

set of volume 1 contains at least one point of Y and at most C? This

discrete geometry problem was posed by Gowers in 2000, and it is a special

case of an open problem posed by Danzer in 1965. I will present two proofs

that answers Gowers' question with a NO. The first approach is dynamical;

we introduce a dynamical system and classify its minimal subsystems. This

classification in particular yields the negative answer to Gowers'

question. The second proof is direct and it has nice applications in

combinatorics. The talk will be accessible to a general audience. [This is

a joint work with Omri Solan and Barak Weiss].