Kai Lai Chung, professor of mathematics emeritus at Stanford and a noted specialist in probability theory, died June 1, 2009. He was 91.

Born in Shanghai, China, Chung earned a bachelor’s (1940) and a master’s degree (1942) from the National Tsinghua University, and then taught there. After the war, in 1947, he earned a Ph.D. in mathematics from Princeton. He then taught at Chicago, Columbia, UC Berkeley, Cornell, and Syracuse. He joined Stanford in 1961 and remained as a professor until retiring in 1988.

In addition to his work in probability, Chung made fundamental contributions in Brownian motion (used to predict seemingly random fluctuations in the stock market). He also worked in Markov processes (in which future events depend on current events and not on past occurrences), and quantum mechanics and potential theory.

In 1981, Chung helped start the popular Seminars on Stochastic Processes, national meetings on probability unique for their informality and encouragement of junior
faculty. Known as an inspirational teacher, he explained with great clarity and strong opinions. Even in his textbooks, he stated that some proofs were more important than others.

Chung was survived by his wife, Lilia; three children; and four grandchildren.

Graduate memorials are prepared by the APGA.

Graduate Class of 1947