J. A. ToddJohn Arthur Todd was an English mathematician who specialised in geometry.BiographyHe was born in Liverpool, and went up to Trinity [College, Cambridge] in 1925. He did research under H.F. Baker, and in 1931 took a position at the University of Manchester. He became a lecturer at Cambridge in 1937. He remained at Cambridge for the rest of his working life.WorkThe Todd class in the theory of the higher-dimensional Riemann–Roch theorem is an example of a characteristic class that was discovered by Todd in work published in 1937. It used the methods of the Italian [school of algebraic geometry]. The Todd–Coxeter process for coset enumeration is a major method of computational algebra, and dates from a collaboration with H.S.M. Coxeter in 1936. In 1953 he and Coxeter discovered the Coxeter–Todd lattice. In 1954 he and G. C. Shephard classified the finite complex [reflection group]s.HonoursIn March 1948 he was elected a Fellow of the Royal Society.Selected publications*