Hugo Hadwiger

Hugo Hadwiger was a mathematician at the University of Bern whose work covered integral geometry, convex and combinatorial geometry, and graph theory. The Mathematics Genealogy Project records his Ph.D. from the Universität Bern in 1936, with a dissertation on the rearrangement of series of analytic functions written under Willy Scherrer, and lists four students of his at Bern between 1951 and 1972, among them Peter Mani and Christoph Meier. His name is attached to Hadwiger's theorem in integral geometry, to the Hadwiger-Nelson problem on colouring the plane, and to the Hadwiger conjecture of 1943, which says that a graph with no complete minor on t vertices can be coloured with fewer than t colours and which generalises the four colour theorem.