Alan Turing, Marshall Hall, and the Alignment of WW2 Japanese Naval Intercepts
Peter Donovan · Notices of the American Mathematical Society · 2014
M arshall Hall Jr. (1910–1990) is deservedly well remembered for his role in constructing the simple group of order 604800 = 27 × 33 × 52 × 7 as well as numerous advances in combinatorics. A brief autobiography is on pages 367–374 of Duran, Askey, and Merzbach [5]. Hall notes that Howard Engstrom (1902–1962) gave him much help with his Ph.D. thesis at Yale in 1934–1936 and later urged him to work in Naval Intelligence (actually in the foreign communications unit Op-20-G). I was in a research division and got to see work in all areas, from the Japanese codes to the German Enigma machine which Alan Turing had begun to attack in England. I made significant results on both of these areas. During 1944 I spent six months at the British Headquarters in Bletchley. Here there was a galaxy of mathematical talent including Hugh Alexander the chess champion and Henry Whitehead the eminent topologist... Burroughs, Lieberman, and Reeds [2] clarified the work of Op-20-G on the Enigma in a contribution to the obituary of Andrew Gleason (1921–2008). Unfortunately the surviving records scarcely allocate credit to individuals. Hall was one of about ten core members of a team of about thirty not far from being another galaxy of mathematical talent. See Christenson [3].