A conjecture on convex polyhedra.
Denote by Kₘ the mirror image of a planar convex body K in a straight line m. It is easy to show that K*ₘ = conv(K ∪ Kₘ) is the smallest by inclusion convex body whose axis of symmetry is m and which contains K. The ratio axs(K) of the area of K to the minimum area of K*ₘ over all straight lines m is a measure of axial symmetry of K. We prove that axs(K) > 1/2√2 for every centrally symmetric convex body and that this estimate cannot be improved in general. We also give a formula for axs(P) for...
We show that whenever the -dimensional Minkowski content of a subset exists and is finite and positive, then the “S-content” defined analogously as the Minkowski content, but with volume replaced by surface area, exists as well and equals the Minkowski content. As a corollary, we obtain the almost sure asymptotic behaviour of the surface area of the Wiener sausage in , .
Let U, V be two symmetric convex bodies in and |U|, |V| their n-dimensional volumes. It is proved that there exist vectors such that, for each choice of signs , one has where . Hence it is deduced that if a metrizable locally convex space is not nuclear, then it contains a null sequence such that the series is divergent for any choice of signs and any permutation π of indices.