This paper studies the undiscounted utilitarian optimal paths of the canonical Dasgupta--Heal--Solow model when the stock of natural capital is a direct argument of well-being, besides consumption. We use a Keynes--Ramsey rule which yields a generalization of Hartwick's rule. We characterize...

This paper studies the undiscounted utilitarian optimal paths of the canonical Dasgupta-Heal-Solow model when the stock of natural capital is a direct argument of well-being, besides consumption. We use a Keynes-Ramsey rule wich yields a generalization of Hartwick's rule : if society has a zero...