What Happened on April 13th

Stan Ulam, a mathematician who did early theoretical work on the use of computers in mathematics, is born in Poland. Ulam teaches at Harvard and the University of Wisconsin before joining the Manhattan Project in Los Alamos, New Mexico, where he meets John von Neumann. There, Ulam and von Neumann discuss using computers to understand questions of pure mathematics. Based on the ENIAC experience, Ulam suggested to von Neumann that neutron diffusion and related chain reactions were natural applications and just as quickly outlined a procedure to implement the notion.