The Poulsen simplex
It is proved that there is a unique metrizable simplex whose extreme points are dense. This simplex is homogeneous in the sense that for every 2 affinely homeomorphic faces and there is an automorphism of which maps onto . Every metrizable simplex is affinely homeomorphic to a face of . The set of extreme points of is homeomorphic to the Hilbert space . The matrices which represent are characterized.