Harry Kesten

Harry Kesten (1931 to 2019) was a Jewish American mathematician best known for his work in probability, most notably on random walks on groups and graphs, random matrices, branching processes and percolation theory. Born in Duisburg, Germany, he grew up in the Netherlands after his parents moved there in 1933 to escape the Nazis, survived the Holocaust, studied chemistry, theoretical physics and mathematics at the University of Amsterdam, and moved to the United States in 1956. He took his PhD at Cornell University in 1958 under Mark Kac, with a thesis on symmetric random walks on groups, and spent most of his career at Cornell. His results include Kesten's criterion for amenability, the Furstenberg and Kesten theorem on products of random matrices, the ratio limit and pattern theorems for self-avoiding walks, the Kesten and Stigum condition for branching processes, and his proof that the critical probability of bond percolation on the square lattice equals one half.