Juris Hartmanis

Juris Hartmanis was a Latvian-born American computer scientist who founded Cornell University computer science department in 1965 and served as its first chair, after earning a PhD in mathematics from Caltech in 1955 and working at General Electric Research Laboratory. Together with Richard E. Stearns, Hartmanis wrote a landmark 1965 paper that formally defined computational complexity classes and proved the time hierarchy theorem, establishing that problems can be rigorously grouped by the amount of computing resources needed to solve them, work now regarded as founding computational complexity theory as a field. Hartmanis shared the ACM Turing Award with Stearns in 1993 in recognition of that seminal paper role in establishing the foundations of the field. He was elected to the National Academy of Engineering in 1989 and the National Academy of Sciences in 2013, and he also received the Grand Medal of the Latvian Academy of Sciences in 2001.