Neil Robertson (mathematician)

George Neil Robertson (born November 30, 1938) is a mathematician working mainly in topological graph theory, currently a distinguished professor emeritus at the Ohio State University.^[1][2]

Robertson earned his B.Sc. from

In 1969, Robertson joined the faculty of the Ohio State University, where he was promoted to Associate Professor in 1972 and Professor in 1984. He was a consultant with Bell Communications Research from 1984 to 1996. He has held visiting faculty positions in many institutions, most extensively at Princeton University from 1996 to 2001, and at Victoria University of Wellington, New Zealand, in 2002. He also holds an adjunct position at King Abdulaziz University in Saudi Arabia.^[2]

Robertson is known for his work in

• In 1964, Robertson discovered the Robertson graph, the smallest possible 4-regular graph with girth five.^[7]
• In 1993, with Seymour and Robin Thomas, Robertson proved the ${\displaystyle K_{6}}$-free case for which the Hadwiger conjecture relating graph coloring to graph minors is known to be true. ^[8]
• In 1996, Robertson, Seymour, Thomas, and Daniel P. Sanders published a new proof of the four color theorem,^[9] confirming the Appel–Haken proof which until then had been disputed. Their proof also leads to an efficient algorithm for finding 4-colorings of planar graphs.
• In 2006, Robertson, Seymour, Thomas, and Maria Chudnovsky, proved the long-conjectured strong perfect graph theorem characterizing the perfect graphs by forbidden induced subgraphs.^[10]

Robertson has won the Fulkerson Prize three times, in 1994 for his work on the Hadwiger conjecture, in 2006 for the Robertson–Seymour theorem, and in 2009 for his participation in the proof of the strong perfect graph theorem.^[11]

He also won the

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