Let us consider a production economy endowed with a single perfectly competitive firm renting at every time both labour and physical capital from the current human population at the real rental rates wy, 13, respectively. In equilibrium at time w, = MPL, andr; = MPK, where MPL, and MPK; denote the marginal product of labour and the marginal product of physical capital, respectively. The aggregate output/income Y; at every time tis produced according to the following Cobb-Douglas production function: Y, = AK} L where A>0 stands for the total factor productivity parameter, K, represents the physical capital and L; denotes the total number of workers with (0,1) is for the labour share of output. Let us assume that the total number of workers corresponds to the size of the aggregate human population at every time : L, = N, which grows at a constant rate ne(0,+w): Neyr = (1 +n)N, where y; = Y; /N, denotes the output/income per capita at time fand k; = K, /N, stands for the physical capital per capita at time & The change in the aggregate physical capital from time fto time +1 is governed by the following equation of motion: Kiyi = LI + (1 - S)Kt where (0,1) represents the physical capital depreciation rate parameter and I, denctes the aggregate investment in physical capital at time which in equilibrium is equal to the aggregate saving: I; = ;.