Optimum Savings and Optimal Growth: the Cass-Malinvaud-Koopmans Nexus

This paper surveys the contributions of David Cass, Tjalling Koopmans, and Edmond Malinvaud over the decades during which modern optimal growth theory was developed. By utilizing material ranging from dissertations, drafts, and working papers, through conference presentations, discussions and published papers, we show that both Malinvaud and Cass had significant impacts on the evolution of Koopman's thought, and the development of his part of what is known as "the Cass-Koopmans model." Based on our findings, we conclude that the modern optimal growth model should include the contributions of Malinvaud, and re-titled "the Cass-Malinvaud-Koopmans" model accordingly.