Dense Pinwheel Packing Is Strongly NP-Complete

An instance of {\sc Pinwheel Packing} is a list of positive integers $a_1,\ldots,a_k$. A feasible schedule assigns one task to every integer time so that every interval of $a_i$ consecutive times contains task $i$. The instance is \emph{dense} when $\sum_i1/a_i=1$. We prove that {\sc Dense P