Fig. 1

Schematic of the population structure. In this simple example, four children \({\mathcal {C}}=\{1,2,3,4\}\) and four adults \({\mathcal {A}}=\{5,6,7,8\}\) are partitioned into three school classes (red circles above), placed into two different buildings (violet rectangles), and two families (green squares below), by means of the functions \(\psi\) and \(\phi\)