George Bergman · CC BY-SA 4.0

Isadore Singer proved the Atiyah–Singer index theorem with Michael Atiyah in 1962, a result that opened new interactions between pure mathematics and theoretical physics and reshaped both fields. He held professorships simultaneously at MIT and the University of California, Berkeley, and in the early 1980s co-founded the Mathematical Sciences Research Institute with Shiing-Shen Chern and Calvin Moore, building an institution that has trained generations of mathematicians since.