Professor Thomas will work on problems related to Wagner's conjecture and Hadwiger's conjecture. He will also investigate whether there is a theory of directed graph minors as well as working in the theory of quasi-ordered sets. Graph Theory goes back perhaps two hundred years, but only in the last half-century has the field become an active, fertile, and flourishing branch of mathematics. A graph is a network of lines ("edges") joining points ("vertices"), thus the language of graphs becomes a natural way of describing interrelationships among separated objects. Graph Theory figures most prominently as an essential tool in Communications Theory and Computer Science.
