algorithm (with Chudnovsky, Scott, and Chudnovsky and Seymour's student Sophie Spirkl) to test whether a graph contains an induced cycle with length more than three and odd. Most recently, the four jointly resolved the 5-cycle case of the Erdős–Hajnal conjecture, which says that every graph without an induced copy of the 5-cycle contains an independent set or a clique of polynomial size. Selected publications See also Robertson–Seymour theorem Strong perfect graph theorem References External links Paul Seymour home page at Princeton University 1950 births Living people 20th-century American mathematicians 21st-century American mathematicians Graph theorists Alumni of Exeter College, Oxford Ohio State University faculty Princeton University faculty People educated at Plymouth College Fellows of Merton College, Oxford Fellows of the Royal Society