Neil Robertson

George Neil Robertson, born on November 30, 1938, is a mathematician working mainly in topological graph theory, a distinguished professor emeritus at the Ohio State University. He earned his B.Sc. from Brandon College in 1959 and his Ph.D. in 1969 at the University of Waterloo under his doctoral advisor William Tutte, and in 1969 joined the faculty of the Ohio State University. He is known for a long series of papers co-authored with Paul Seymour, published over many years, in which they proved the Robertson-Seymour theorem, formerly called Wagner's Conjecture, which states that families of graphs closed under the graph minor operation may be characterized by a finite set of forbidden minors. In 1964 he discovered the Robertson graph, the smallest possible 4-regular graph with girth five.