2008-2009

Mike O'Neill

**Monday, November 24
Millikan 213
(Pomona College), 3:00 PM**

**Title: **Bang's solution
of the Tarski plank
problem

Abstract: I will present Bang's proof of the Tarski plank conjecture as a continuation of Lenny Fukshansky's last talk. The proof is elementary and no knowledge of the previous talk is necessary to understand it. The abstract of Lenny's talk is included below.

In 1932 A. Tarski
conjectured that if a convex body in R^N is covered by a finite
collection of planks (strips of space between parallel hyperplanes),
then the sum of widths of these planks must be at least the minimal
width of the convex body. Tarski himself proved this conjecture for the
case of a disc in R^2, and the general form of this conjecture was
proved by T. Bang in 1951. Various generalizations of Tarski's problem
have been studied by different authors more recently as well, for
instance K. Ball in 1990 studied an interesting version of Tarski's
problem in normed linear spaces. We will review some results in this
area, and will also discuss certain discrete analogues of the Tarski
plank problem.