Helly's theorem?

Who?
Mareike Massow (TU Berlin)
When?
2009/02/06, 13:00
Before the BMS Friday Colloquium by Prof. Gil Kalai
Where?
Urania Berlin, at the BMS Loft
Helly's Theorem is one of the most famous results of a combinatorial nature about convex sets. It states that if we have $n$ convex sets in $\mathbb R^d$, where $n>d$, and the intersection of every $d+1$ of these sets is nonempty, then the intersection of all sets is nonempty. In preparation of Gil Kalai's BMS talk, we will see a basic proof of this theorem using (a basic proof of) Radon's Lemma. Hopefully we will also have a look at some application(s).