He is a member of the National Academy of Sciences of the United States, a foreign member of the Paris Academy of Sciences and the Soviet Academy of Sciences. He won the Wiener Award for Applied Mathematics (1975) and Steele Award for Lifelong Achievement (1993) from the American Mathematical Society, the Applied Mathematics Award from the National Academy of Sciences (1983), national medal of science award (1986) and so on. 49636.888686866866