Roger David Nussbaum

Roger 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.

• with Bas Lemmens: Nonlinear Perron-Frobenius Theory, Cambridge Tracts in Mathematics, Cambridge University Press 2012
• with S. M. Verduyn-Lunel: Generalizations of the Perron-Frobenius Theorem for Nonlinear Maps, Memoirs AMS 1999
• with Heinz-Otto Peitgen: Special and Spurious Solutions of ${\displaystyle {\dot {x}}(t)=-\alpha f(x(t-1))}$, Memoirs AMS, 1984
• with Patrick Fitzpatrick, Jean Mawhin, Mario Martelli: Topological Methods for Ordinary Differential Equations, CIME Lectures, Montecacini Terme 1991, Lecture Notes in Mathematics 1537, Springer Verlag 1993
• Hilbert's projective metric and iterated nonlinear maps, 2 vols., AMS 1988
• Differential-delay equations with two time lags, Memoirs AMS 1978