Marcel Kessel (Ket) Richer, a retired University of Minnesota professor of economics, died July 11. He was born in New York, N.Y., in 1932; was raised in Leonia, N.J.; and graduated from Birch Wathen School, Swarthmore College, and MIT.
Ket used tools from mathematical logic and set theory to develop powerful methods for understanding fundamental economic questions of consumer preferences, rationality, choice, coalition formation, competition, and equilibrium. His work on revealed preference is widely applied to analyze and predict behavior by rational agents. Following his vision, generations of economists have used mathematical tools to develop simple techniques for analyzing complex problems.
Always deeply curious and passionate about ideas, Ket was a spirited colleague, dedicated mentor and lifelong learner. At his death, he was preparing a new theory on intensity of preference.
Ket met his beloved wife, Sheila Mills Richter, at Swarthmore. They wed upon graduation in 1954 and remained lovingly married until her death in 2011. Both were members of the Prospect Hill Friends Meeting.
He was preceded in death by his wife and parents, Maurice Nathaniel Richter and Brina Hirshfield Kessel Richter. He is survived by daughters Cynthia Reis-Richter (Martha) of Minneapolis and Leila Fiester (Reid) of Frederick, Md.; grandchildren Solea Fiester and Carlos Reis-Richter; and brothers Maurice N. Richter, Jr. and Wayne Richter (Anne White).
