Michael Dobbins (Center for Geometry and Its Applications (GAIA), Pohang)

Abstract for the Colloquium 2014 December 12

I show that it is always possible to find n points in the d-dimensional faces of an nd-dimensional convex polytope P so that their center of mass is a target point in P. Equivalently, the n-fold Minkowski sum of the polytope's d-skeleton is the polytope P scaled by n. This verifies a conjecture by Takeshi Tokuyama.