Published online by Cambridge University Press: 20 November 2018
In 2012, Gubeladze (Adv. Math. 2012) introduced the notion of $k$ -convex-normal polytopes to show that integral polytopes all of whose edges are longer than
$4d(d+1)$ have the integer decomposition property. In the first part of this paper we show that for lattice polytopes there is no diòerence between
$k$ - and
$(k+1)$ -convex-normality (for
$k\ge 3$ ) and improve the bound to
$2d(d+1)$ . In the second part we extend the definition to pairs of polytopes. Given two rational polytopes
$P$ and
$\text{Q}$ , where the normal fan of
$P$ is a refinement of the normal fan of
$\text{Q}$ , if every edge
${{e}_{P}}$ of
$P$ is at least
$d$ times as long as the corresponding face (edge or vertex)
${{e}_{\text{Q}}}$ of
$\text{Q}$ , then
$(P+\text{Q})\cap {{\mathbb{Z}}^{d}}=(P\cap {{\mathbb{Z}}^{d}})+(\text{Q}\cap {{\mathbb{Z}}^{d}})$ .