Gabriel Andrew Dirac
Gabriel Andrew Dirac (13 March 1925 – 20 July 1984) was a Hungarian/British mathematician who mainly worked in graph theory. He served as Erasmus Smith's Professor of Mathematics at Trinity College Dublin 1964-1966. In 1952, he gave a sufficient condition for a graph to contain a Hamiltonian circuit. The previous year, he conjectured that n points in the plane, not all collinear, must span at least formula_1 two-point lines, where formula_2 is the largest integer not exceeding formula_3. This conjecture was proven true when n is sufficiently large by Green and Tao in 2012 . Education. Dirac started his studies at St John's College, Cambridge in 1942, but by 1942 the war saw him serving in the aircraft industry. He received his MA in 1949, and moved to the University of London, getting his Ph.D. "On the Colouring of Graphs: Combinatorial topology of Linear Complexes" there under Richard Rado. Career. Dirac's main academic positions were at the King's College London (1948-1954), University of Toronto (1952-1953), University of Vienna (1954-1958), University of Hamburg (1958-1963), Trinity College Dublin (Erasmus Smith's Professor of Mathematics, 1964-1966), University of Wales at  Swansea (1967-1970), and Aarhus University (1970-1984). Family. He was born Balázs Gábor in Budapest, to Richárd Balázs, a military officer and businessman, and Margit "Manci" Wigner (sister of Eugene Wigner). When his mother married Paul Dirac in 1937, he and his sister resettled in England and were formally adopted, changing their family name to Dirac.