John Leech (mathematician)

John Leech ( born July 21, 1926 in Weybridge, Surrey, † September 28, 1992 in Scotland ) was an English mathematician who worked on number theory, geometry and combinatorial group theory. He discovered in 1964, the Leech lattice.

Life and work

John Leech attended Trent College, Derbyshire and attended Kings College in Cambridge, where in 1950 his bachelor's degree in mathematics made ​​. He then worked at Ferranti in Manchester in the development of early computer. In 1954 he returned to Cambridge as a Research Student. In 1959 he was Lecturer in the Computing Laboratory of the University of Glasgow. 1967/68 he was a Research Fellow at the Atlas Computer Laboratory at Harwell. In 1968 he went to the newly founded University of Stirling, where he taught computer science at a personally designed for him the chair. In 1980 he took early retirement for health reasons.

Leech turned an early stage in the computer numerical algebra to, for example, he implemented the Todd - Coxeter algorithm for enumerating the cosets of a group. He became famous for his discovery (1964 ) of the Leech lattice, the lattice of a dense sphere packing in 24 dimensions, which is important for the realization of the sporadic simple groups. For example, John Conway introduced three new sporadic groups as symmetry groups of the Leech lattice. Before Leech himself had tried in vain to interest other group theorists and geometer HSM Coxeter, such as, John Arthur Todd and Graham Higman for the study of the symmetry group of its lattice.

1956 John Leech was in a short note a new proof of the kiss - number problem in three dimensions, that is more than twelve equal spheres can touch a central ball. First, the Bartel Leendert van der Waerden and Kurt Schütte had proved 1953. His proof, however, was shown very sketchy .. But he was considered very elegant and has been included even by Aigner and Ziegler in the first edition of her book Proofs from the Book.

Leech suffered aboard the historic paddle steamer " Waverley " a heart attack when he was traveling at the last ride of the season between Rothesay and Largs. Leech was part of the support group of the steamer. He was married to the British physicist Jenifer Haselgrove.