Donald Jay Geman (born September 20, 1943) is an American applied mathematician and a leading researcher in the field of machine learning and pattern recognition. He and his brother, Stuart Geman, are very well known for proposing the Gibbs sampler and for the first proof of the convergence of the simulated annealing algorithm, in an article that became a highly cited reference in engineering (over 21K citations according to Google Scholar, as of January 2018). He is a professor at the Johns Hopkins University and simultaneously a visiting professor at École Normale Supérieure de Cachan. Source: Wikipedia (en)