Tien-Yien Li


Tien-Yien Li was a University Distinguished Professor of Mathematics and University Distinguished Professor Emeritus at Michigan State University after spending 42 years at the university and supervised twenty-six Ph.D. dissertations.

Early life and education

Li was born on June 28, 1945 in Sha County, Fujian Province, China. At age three, he was brought to Taiwan by his parents. He earned his B.S. in Mathematics at the National Tsinghua University in 1968. Li received his doctorate in 1974 from University of Maryland under the guidance of Dr. James Yorke.

Academic career

Li joined the faculty of the Department of Mathematics at Michigan State University in 1976 and was promoted to the rank of full professor in 1983. He retired as a University Distinguished Professor Emeritus in 2018 after spending 42 years at the university. Li and co-author James Yorke published a monumental paper in 1975 entitled Period three implies chaos, in which the mathematical term chaos was coined. His proof of Ulam's conjecture is yet another pioneering work in the computation of invariant measures of chaotic dynamical systems. Working with Kellogg and Yorke, Li's ideas and the use of numerical methods in computing Brouwer's fixed point, opened up a new era in the research of the modern Homotopy Continuation methods.

Awards and honors