Published online by Cambridge University Press: 20 November 2018
Let $K$ be a convex body in
${{\mathbf{E}}^{d}}$ and denote by
${{C}_{n}}$ the set of centroids of
$n$ non-overlapping translates of
$K$. For
$\varrho \,>\,0$, assume that the parallel body conv
${{C}_{n}}\,+\,\varrho K$ of conv
${{C}_{n}}$ has minimal volume. The notion of parametric density (see [21]) provides a bridge between finite and infinite packings (see [4] or [14]). It is known that there exists a maximal
${{\varrho }_{s}}(K)\,\ge \,1/(32{{d}^{2}})$ such that conv
${{C}_{n}}$ is a segment for
$\varrho \,<\,{{\varrho }_{s}}$ (see [5]). We prove the existence of a minimal
${{\varrho }_{c}}(K)\,\le \,d\,+\,1$ such that if
$\varrho \,>\,{{\varrho }_{c}}$ and
$n$ is large then the shape of conv
${{C}_{n}}$ can not be too far from the shape of
$K$. For
$d\,=\,2$, we verify that
${{\varrho }_{s\,}}\,=\,{{\varrho }_{c}}$. For
$d\,\ge \,3$, we present the first example of a convex body with known
${{\varrho }_{s}}$ and
${{\varrho }_{c}}$; namely, we have
${{\varrho }_{s}}\,=\,{{\varrho }_{c}}\,=\,1$ for the parallelotope.