Mark David Haiman is a mathematician at the University of California at Berkeley who proved theMacdonald positivity conjecture for Macdonald polynomials. He received his Ph.D in 1984 in the Massachusetts Institute of Technology under the direction of Gian-Carlo Rota. Previous to his appointment at Berkeley, he held a position at the University of California, San Diego.In 2012 he became a fellow of the American Mathematical Society.