Richard Stearns

Richard Edwin Stearns is an American computer scientist and Distinguished Professor Emeritus of Computer Science at the University at Albany, part of the State University of New York, who earned his PhD in mathematics from Princeton University in 1961 under Harold W. Kuhn. With Juris Hartmanis, Stearns co-authored a foundational 1965 paper that formally defined computational complexity classes and proved the time hierarchy theorem, work now recognized as having established computational complexity theory as a field of study. Stearns and Hartmanis shared the ACM Turing Award in 1993 for that seminal paper, and Stearns was inducted as a Fellow of the Association for Computing Machinery in 1994 and received the Frederick W. Lanchester Prize in 1995. His broader research contributed to the theory of regular expressions, pushdown automata and compiler design.