Delbert Ray Fulkerson (/ˈfʌlkərsən/; August 14, 1924 – January 10, 1976) was an American mathematician who co-developed the Ford–Fulkerson algorithm, one of the most well-known algorithms to solve the maximum flow problem in networks.

D. R. Fulkerson was born in Tamms, Illinois, the third of six children of Elbert and Emma Fulkerson. Fulkerson became an undergraduate at Southern Illinois University. His academic career was interrupted by military service during World War II. Having returned to complete his degree after the war, he went on to do a Ph.D. in mathematics at the University of Wisconsin–Madison under the supervision of Cyrus MacDuffee, who was a student of L. E. Dickson. Fulkerson received his Ph.D. in 1951.^[2]

After graduation, Fulkerson joined the mathematics department at the RAND Corporation. In 1956, he and L. R. Ford Jr. described the Ford–Fulkerson algorithm.^[3] In 1962 they produced a book-length description of their method.^[4]

In 1971 he moved to Cornell University as the Maxwell Upson Professor of Engineering. He was diagnosed with Crohn's disease and was limited in his teaching. In despair, he committed suicide in 1976.^[5]

Fulkerson was the supervisor of Jon Folkman at RAND and Tatsuo Oyama^[6] at GRIPS. After Folkman committed suicide in 1969, Fulkerson blamed himself for failing to notice Folkman's suicidal behaviors.^[7]

In 1979, the renowned Fulkerson Prize was established which is now awarded every three years for outstanding papers in discrete mathematics jointly by the Mathematical Programming Society and the American Mathematical Society.

• Out-of-kilter algorithm
• List of people diagnosed with Crohn's disease