“…Many population models consider the values of the time-dependent density in the Lebesgue-Bochner space L 1 ([s min , s max ]; Y ) where Y denotes a real Banach space of functions defined on R (see, e.g., [7,8,13,33,52,68,85] and references therein). This rearrangement of variables opens the door to semigroup approaches (with linear or nonlinear operators in Banach spaces, see, e.g., [35,36,37,38,55,75,76,87,88,89] and references therein).…”