Garrett Birkhoff, mathematician (1911-1996)

Birkhoff was a Harvard mathematician, the son of George Birkhoff. I saw Birkhoff once or twice, but never met him. I lectured at Harvard in 1990 or 1991 using his theorem about bistochastic matrices in analysing kinetic equations; this talk was well received by Bott. For a reference to books that deal with the theorem mentioned in the title of my paper with Larry Landau, see part of the appreciation by Philip Davis.