Person: Leech, John

John Leech was an English mathematician who is best known for the Leech lattice which is important in the theory of finite simple groups.

After graduating Leech was appointed to a post with Ferranti in Manchester where he worked on the construction of an early digital computer.
In 1954 Leech left Ferranti to return to Cambridge, becoming a research student in the mathematical laboratory.
Leech was appointed as Reader and first Head of Computing Science at Stirling.
Leech is, however, best known for the Leech lattice which gives rise to three sporadic simple groups.
In 1965 he submitted a supplement to the paper giving a packing in 24 dimensions with a lattice now known as the Leech lattice.
Leech knew that the symmetry group would be interesting, and he worked on it for some time giving a lower bound for its order (which later proved to be the actual order of the group).
A few weeks before his death, Leech visited us in St Andrews on each day for about a week and four of us worked on a number of problems which had been left unsolved by Leech 30 years before.
Leech died almost exactly one month after Gorenstein who had overseen the classification of finite simple groups.
The three sporadic groups which Conway deduced from Leech's lattice play an important role in the classification.

Born 21 July 1926, Weybridge, Surrey, England. Died 28 September 1992, On board the SS Waverley, at sea between Rothesay and Largs, Scotland.

View full biography at MacTutor

Group Theory, Origin England

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O’Connor, John J; Robertson, Edmund F: MacTutor History of Mathematics Archive