Roger D. NussbaumRoger David Nussbaum (born 29 January 1944 in Philadelphia) is an American mathematician, specializing in nonlinear functional analysis and differential equations.
Nussbaum graduated in 1965 with a bachelor's degree from Harvard University. He received his Ph.D. in 1969 from the University of Chicago with thesis ''The Fixed Point Index and Fixed Point Theorems for K-Set Contractions'' supervised by Felix Browder. At Rutgers University Nussbaum became in 1969 an assistant professor, in 1973 an associate professor, and in 1977 a full professor. He retired there as professor emeritus. He was elected in 2012 a Fellow of the American Mathematical Society. Provided by Wikipedia