Isadore Singer

Isadore Manuel Singer (May 3, 1924 – February 11, 2021) was an American mathematician. He was an Institute Professor in the Department of Mathematics at the Massachusetts Institute of Technology and a Professor Emeritus of Mathematics at the University of California, Berkeley. 
Singer was known for his work with Michael Atiyah proving the Atiyah–Singer index theorem in 1962. 
Singer died on February 11, 2021 at his home in Boxborough, Massachusetts at the age of 96.