“…| · | Eucl and P Eucl (·). The isoperimetric problem with single density is a wide generalisation of the classical Euclidean isoperimetric problem, and it has been deeply studied in the last decades, we refer the interested reader to [8,10,11,16,22,25,28,29,32] and the references therein. The case of double density is yet a further important generalisation, since many of the possible applications correspond to two different densities.…”