John Leech (mathematician)

from Wikipedia, the free encyclopedia

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

Live and act

John Leech attended Trent College in Derbyshire and Kings College in Cambridge , where he received his bachelor's degree in mathematics in 1950. He then worked at Ferranti in Manchester on early computer development. In 1954 he returned to Cambridge as a research student. In 1959 he became a lecturer in the Computing Laboratory at 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 in a chair set up for him personally. In 1980 he took early retirement for health reasons.

Leech used computers in numerical algebra early on, for example he implemented the Todd-Coxeter algorithm to enumerate the secondary classes of a group. He became famous for his discovery (1964) of the Leech lattice, the lattice of a close packing of spheres in 24 dimensions, which is important for the construction of the sporadic simple groups. For example, John Conway derived three new sporadic groups as symmetry groups of the leech lattice. Before that, Leech himself had tried in vain to interest other group theorists and geometers such as HSM Coxeter , John Arthur Todd and Graham Higman in studying the symmetry group of his lattice.

In 1956, John Leech gave a new proof of the kiss number problem in three dimensions in a short note , that a maximum of twelve other balls of the same size can touch a central ball. First, the had Bartel Leendert van der Waerden and Kurt Schuette proved 1,953th His proof, however, was very sketchy. However, it was considered very elegant and was therefore even included by Aigner and Ziegler in the first edition of their book Proofs from the Book .

Leech suffered a heart attack on board the historic paddle steamer "Waverley" when it was on the last voyage of the season between Rothesay and Largs. Leech was part of the steamer's support group. He was married to the British physicist Jenifer Haselgrove .

literature

  • Thompson: From error correcting codes through sphere packings to finite simple groups. Washington 1983.
  • Leech: Note on sphere packing. Canadian Journal of Mathematics, Vol. 19, 1967, p. 251.
  • Leech: Some sphere packings in higher space. Canadian Journal of Mathematics, Vol. 16, 1964, p. 657.
  • Leech: The problem of the 13 spheres. Mathematical Gazette, Vol. 40, 1956, p. 22.

Web links

References

  1. ^ The Mathematical Gazette, Vol. 40, 1956, pp. 22-23
  2. ↑ With additions by the authors, which turned out to be inadequate. It was taken out again in later editions. Casselman on the Kissing Number Problem, Notices of the AMS, 2004, Issue 8, PDF file
personal data
SURNAME Leech, John
BRIEF DESCRIPTION English mathematician
DATE OF BIRTH July 21, 1926
PLACE OF BIRTH Weybridge , Surrey
DATE OF DEATH September 28, 1992
Place of death Scotland