Pinching and Asymptotical Roundness for Inverse Curvature Flows in Euclidean Space

We consider inverse curvature flows in the $(n+1)$-dimensional Euclidean space, $n\geq 2,$ expanding by arbitrary negative powers of a 1-homogeneous, monotone curvature function $F$ with some concavity properties. We obtain asymptotical roundness, meaning that circumradius minus inradius of the flow hypersurfaces decays to zero and that the flow becomes close to a flow of spheres.Comment: 13 pages. In this final version we were able to remove the dimension restrictions which had to be imposed in the former versions. Comments, discussions or suggestions are welcom