Joris Hartmanisa Turing Prize Winner The pioneer who was instrumental in establishing computer science as an independent field, and the founding chair of the computer science department at Cornell University, died on July 29 at the age of 94.
Hartmanis, often called the “father of computational complexity,” discovered a set of fundamental laws that govern computational difficulty, laying the foundation for a comprehensive theory of the efficiency and limits of computing.
At Cornell, Hartmanis built one of the world’s first computer science departments.
“Juris was a visionary researcher, a leader and an educator,” said Kavita Bala, dean of Cornell’s Ann S. Powers College of Computing and Information Sciences. “His legacy lives on in the discipline he helped build and in the minds of many people who, like me, have been an inspiration.”
Hartmanis was born in Riga, Latvia, in 1928. His father, a general in the Latvian army, died in prison after the Soviet occupation of Latvia in the 1940s, which prompted Hartmanis and his family to emigrate to Germany. He completed his high school education in a camp for the homeless and earned a bachelor’s degree in physics from the University of Marburg. Sponsoring a family friend, he moved to the United States and earned a master’s degree in mathematics from Kansas City University (now the University of Missouri-Kansas City) in 1951 and a Ph.D. in Mathematics from Caltech in 1955.
From 1955 to 1957 he was a mathematics teacher at Cornell University, followed by nine months as an assistant professor of mathematics at Ohio State University. In 1958, he was seduced by industrial research and joined the General Electric (GE) Research Laboratory in Schenectady, New York, where he spent the next seven years.
At GE he and colleague Richard Stearns founded the field of computational complexity, a field of research that remains a central topic in computer science to this day. There has been previous work in analyzing algorithms that attempted to establish upper or lower time limits on specific algorithms for different computational problems, but very few general principles have united the behavior of these algorithms.
Their main contribution was the study of the inherent complexity of the problems themselves. In their 1965 paper, “About the computational complexity of algorithmsThey defined the basic concept of a complexity class – a class of problems that can be solved within a specified time on a multi-band Turing machine. They show that this idea is very powerful in the sense that complexity classes are timescale independent and not amenable to subtle changes in the machine model, thus The results were relevant to any reasonable computational model.They demonstrated many theories regarding the separation and containment of complexity classes, thus establishing the existence of an infinite hierarchy of complexity classes.
For this foundational work, Hartmanis and Stearns were awarded the 1993 Turing Prize, the first honor in computer science.
In 1965, Hartmanis returned to Cornell as the first head of the newly founded Department of Computer Science. Under his leadership, graduates became faculty members in new computer science departments formed across the country.
“Juris has been an inspiration to generations of computer scientists since the early days of the field,” said Dexter Cousin, Joseph Newton Bio Jr. Professor of Engineering in the Department of Computer Science. “I am fortunate to have studied under Joris at Cornell, where his influence on the department’s culture is still felt to this day. The news of his death left me with a deep sense of loss, which I am sure is true with many.”
Hartmanis served as chair of the department three times – 1965-1971, 1977-83 and 1992-93 – and eventually retired from the university in 2001 as Professor Walter R.
“We have a lot to thank for the law,” said Eva Tardus, professor of computer science and chair of the computer science department, Eva Tardus. “He established our department, and he established the collegiate and collaborative culture that has helped us be an amazing department to this day.”
In addition to his service to Cornell, Hartmanis has contributed to national efforts to advance the field of computer science. He headed a study of the National Research Council that resulted in the publication in 1992, “Computing the future: a broader agenda for computer science and engineering. The report set a research agenda and recommended a framework for education, finance, and leadership designed to bring computing into the twenty-first century.
From 1996 to 1998, Hartmanis served as assistant director of the National Science Foundation, where he led the Directorate of Computer and Information Science and Engineering (CISE). There, he led efforts to turn the NSFnet academic research network into the early Internet.
He also served on the Science Council and the Scientific Steering Committee of the Santa Fe Institute, an independent, non-profit research group established to advance research in complexity science.
Among his many awards, Hartmanis has been a member of the American Academy of Arts and Sciences, the National Academy of Engineering, the National Academy of Sciences, and the Latvian Academy of Sciences, and a fellow of the Society for Computing Machines and the American Mathematical Society. He received the Bolzano Gold Medal from the Academy of Sciences of the Czech Republic and the Computing Research Consortium’s Distinguished Service Award. In 1993, he was awarded the Senior American Scientist Award from the Humboldt Foundation, and received honorary doctorates from the University of Missouri and the University of Dortmund.
Joris died by his wife, Ellie (Rewaldt), and was survived by three children: Reneta McCarthy, Martin Hartmanis, and Audrey Langkammer.
The family is asking for donations in place of flowers to be sent to Ithaca Scienceenter in his memory. The Life Celebration at Ithaca Yacht Club will take place on August 15, noon – 2pm
Patricia Waldron is a staff writer at Cornell’s Ann S. Powers College of Computing and Information Sciences.