A point set `$S$`

in `$\mathbb{R}^d$`

is called a Delone set, if it is uniformly discrete and relatively dense; i.e., if there are numbers `$R>r>0$`

, such that each ball of radius `$r$`

contains at most one point of `$S$`

, and every ball of radius `$R$`

contains at least one point of `$S$`

.