"Sir Christopher Zeeman, the mathematician, who has died aged 91, had a unique combination of mathematical and administrative abilities, allied to an overwhelming personal charm. Zeeman’s career had five distinct phases: as a brilliant topologist at Cambridge (1947-1964); as the Founding Professor of Mathematics at Warwick who created the Warwick Mathematics Institute (1964-1988); as the propagator of catastrophe theory and its applications (1970s); as the public face of mathematics in the 1970s and 1980s, and as the Principal of Hertford College, Oxford, from 1988 to 1995. After war service as an RAF navigator, Zeeman was at Cambridge from 1947 until 1964, as an undergraduate, then graduate student, research fellow and lecturer. Initially, he was a conventional mathematician, working in topology, the geometry of curved spaces in many dimensions. In his PhD thesis he developed “dihomology”, an ingenious algebraic technique for counting the local singularities of a topological space by the failure of the manifold Poincaré duality. Technically, this was a failed proof of the 3-dimensional Poincaré conjecture for deciding if a space is a 3-dimensional sphere. This was only proved in 2003 by Perelman. But in the 1980s Zeeman’s dihomology led to the powerful method of “intersection homology” in pure mathematics of spaces with singularities. It may yet find an application in “big data” science, which is currently so fashionable, as a method for the recognition of the topological features of large data sets." http://www.telegraph.co.uk/news/obituaries/12194628/Sir-Christopher-Zeeman-mathematician-obituary.html
