Joel Smoller, 81, a recently retired professor of mathematics at the University of Michigan, died Sept. 27 after a prolonged illness.

He was born and raised in Brooklyn, the son of a New York City taxi driver. Despite the hardship of losing his mother at an early age, and with the support of his extended family, he pursued academics in the public schools. He found his love of math in his first geometry course in high school, and then never waivered in his desire to become a mathematician. He attended New York University for his undergraduate degree, and Purdue University for his Ph.D. in 1963.

His first and only academic appointment was at the U-M Department of Mathematics. His 54-year career here began in 1963 as an instructor. Smoller was promoted to professor in 1970, and was named the Lamberto Cesari Collegiate Professor of Mathematics in 1998. He retired from active faculty status in June 2017. Smoller’s long and prestigious academic career includes supervising 28 graduate students and mentoring many postdoctoral faculty, producing more than 180 publications in association with 34 co-authors, and teaching hundreds of undergraduate and graduate students.

He specialized first in partial differential equations, but his research regularly grew into different fields as a new passion took hold. He conducted research in shock-wave theory; Navier-Stokes equations; systems of reaction-diffusion equations; stellar dynamics; dynamical systems (Conley Index Theory); and bifurcation theory (symmetry-breaking bifurcations).

Smoller pioneered the analysis of numerical difference schemes for conservation laws in several space dimensions, introduced new topological methods to the analysis of partial differential equations, and was fundamental in establishing the shock structure problem in mathematics. Many of his early results have been influential in mathematical biology.

His more recent research concerned Stability of Kerr (rotating) Black Holes under various perturbations such as scalar waves, Dirac Fields, electromagnetic waves, and gravitational waves; and astrophysical shock-waves, concerned with astrophysical problems including an explanation of the anomalous acceleration of the universe, wholly within Einstein’s equations of General Relativity and avoiding the cosmological constant, and the notion of dark energy. His book, “Shock Waves and Reaction — Diffusion Equations” became the standard in that area and has been a reference in programs worldwide.

During his career, Smoller received significant recognition for his scholarly activities including a Guggenheim Fellowship in 1980, the Margaret and Herman Sokol Award in 1992, and an Excellence in Research Award in 1996. More recently he was named a senior Humboldt Fellow, and received the G.D. Birkhoff Prize in Applied Mathematics from AMS/SIAM in 2009. The Birkhoff prize is awarded jointly by the American Mathematical Society and the Society for Industrial and Applied Mathematics once every three years to recognize an outstanding contribution to “applied mathematics in the highest and broadest sense.” There, Smoller was cited for his leadership, originality, depth and breadth of work in dynamical systems, differential equations, mathematical biology, shock wave theory and general relativity. Three special issues of the journal, Methods and Applications of Analysis were dedicated to him and featured a photograph of him on the front covers.

From his home base at Michigan, Smoller became a citizen of the world. He loved to travel and meet new people, and was a frequent speaker at international conferences and seminars. During his career, he also was a visiting member at Courant Institute of Mathematical Sciences, and a visiting professor at the University of Wisconsin, the University of Paris, and Ecole Normale Superieure in Paris. He spent sabbatical leaves at the University of Warwick, Harvard University, and University of California, Davis.

Smoller had a passion for math and would sometimes spend spare time returning to some problem on his desk. He also spent significant time on the tennis and squash courts. He continued to jog and to play squash until a serious injury slowed him down. Even then, he kept up a regular exercise program and would not be stilled. He was also known for his subtle and appreciative sense of humor. He was a kind, giving individual with an endearing quirkiness, who was only ferocious about math and politics.

He loved to spend time at the lake in summer and Florida in the winter, and enjoyed entertaining, and hosting people in his home. He valued his family above all, and had a great enthusiasm for life. He was happiest when surrounded by family and friends, enjoying good food and wine in their company.

Smoller is survived by his wife Margaret; children, Debbie, Alex (Lisa Mitchell), and Sally; his stepchildren Anne Dickinson (Patrick) and David Arditti; his granddaughter, Arcadia Mitchell; his brother Howard; and his many friends, coauthors, and colleagues here and abroad.

Smoller’s research was funded by National Science Foundation grants for almost his entire career, and he supported many students to the maximum possible. He leaves behind a large number of math professors and professionals whom he nurtured and mentored through their academic training and into their careers; many began as students and ended as close friends and coauthors. He cared deeply about mentoring and supporting his students. To carry on this tradition, a scholarship has been established in his name to benefit graduate mathematics students working in his area of expertise, partial differential equations associated with physical processes. Memorial contributions can be made to the Joel Smoller Fellowship Fund in the Department of Mathematics (fund #700262). Contributions can be sent via mail to the U-M Department of Mathematics, 530 Church Street, Ann Arbor, MI 48109-1043 (checks to University of Michigan), or at victo.rs/2y3Yohi.

— Submitted by the Smoller family