Oscar Lanford

In 2012 he became a fellow of the American Mathematical Society.

Lanford was the recipient of the 1986 United States National Academy of Sciences award in Applied Mathematics and Numerical Analysis and holds an honorary doctorate from Wesleyan University.

Campanino and Epstein also gave a proof of the fixed point without computer assistance but did not establish its hyperbolicity. They cite in their paper Lanfords computer assisted proof. There are also lecture notes of Lanford from 1979 in Zurich and announcements in 1980. The hyperbolicity is essential to verify the picture discovered numerically by Feigenbaum and independently by Coullet and Tresser. Lanford later gave a shorter proof using the Leray-Schauder fixed point theorem but establishing only the fixed point without the hyperbolicity. Lyubich published in 1999 the first not computer assisted proof which also establishes hyperbolicity. Work of Sullivan later showed that the fixed point is unique in the class of real valued quadratic like germs.

Born in New York, Lanford was awarded his undergraduate degree from Wesleyan University and the Ph.D. from Princeton University in 1966 under the supervision of Arthur Wightman. He has served as a professor of mathematics at the University of California, Berkeley, and a professor of physics at the Institut des Hautes Études Scientifiques (IHES) in Bures-sur-Yvette, France (1982-1989). Since 1987, he was with the department of mathematics, Swiss Federal Institute of Technology Zürich (ETH Zürich) till his retirement. After his retirement, he taught occasionally in New York University.

Oscar Eramus Lanford III (January 6, 1940 – November 16, 2013) was an American mathematician working on mathematical physics and dynamical systems theory.