Professor David Kendall

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Father of British probability

David Kendall was the first Professor of Mathematical Statistics at Cambridge University and the founding father and grand old man of British probability.

Kendall was born in Ripon, Yorkshire in 1918. He attended Ripon Grammar School, where he became interested in astronomy. His mathematical talents were recognised early and encouraged - one teacher gave Kendall his Cambridge Part I lecture notes, and he was reading scholarship material in his early teens. He won a scholarship to Queen's College, Oxford in 1936.

At Queen's, he was tutored by U.S. Haslam-Jones, encouraged in his astronomical interests by the astronomer Professor E. A. Milne and taught analysis by Professor E.C. Titchmarsh. When he graduated in 1939, he won a scholarship for research in astronomy (he had already published his first paper in the field in 1938 - "Effect of Radiation Damping and Doppler broadening on the Atomic Absorption Coefficient" in Zeitschrift fr Astrophysik), but with mixed feelings, as he was deeply in love with mathematics, particularly analysis. As he put it, "I was still torn between the two subjects and couldn't see how the conflict would be resolved, but Hitler resolved it for me."

Like other brilliant young mathematicians of the time, Kendall soon became involved in war work. In March 1940, he began work with the Projectile Development Establishment, where he worked on rockets. As a result of the forced evacuations from Dunkirk and Norway, the British Army had had to abandon most of its heavy equipment, in particular artillery. Rocket development acquired a high priority to fill this gap, since less metal and heavy engineering is needed. But on the other hand, rockets are inherently less accurate than artillery shells, which are guided on their way by the gun barrel - just as a rifle is more accurate than a pistol. Study of the errors, or deviations from the intended trajectory, was crucially important, and as these errors are random, this made a study of the mathematics of randomness - probability and statistics - of prime importance. Kendall had to learn this material from scratch. These efforts led to the successful development of rockets used in massed batteries from assault ships at D Day, and the deadly deployment of rocket-firing Typhoon fighters as tank-busters in Normandy.

After the war, Kendall naturally wished to return to academia, and on the strength of his wartime work, still classified, he was appointed Mathematics Tutor at Magdalen College, Oxford in 1946, a post he filled happily for 16 years. His research, now and for the rest of his life, firmly focused on probability and statistics, flourished during this period.

One highlight was his pioneering work of 1949 on stochastic (or random) processes for population growth. Another was his classic 1951 paper on queuing theory, which was motivated by the scheduling problems of aircraft and runways during the Berlin air lift of 1948- 49. A third was a series of penetrating studies, with G.E.H. Reuter, of Markov processes (roughly, random processes without memory).

Cambridge University had had a Statistical Laboratory de facto since 1947 and officially since 1953, and in the early Sixties it was decided to appoint a Professor of Mathematical Statistics. …