Lethbridge Number Theory and Combinatorics Seminar: Luke Morgan

The use of graphs to study permutation groups goes back to Higman who first introduced the orbital graphs, and used them to characterise the primitive groups. Since then, graph theory and permutation group theory have become intertwined, with many beautiful results. In this talk, I will discuss some problems which lie across the boundary of permutation group theory and graph theory (or at least algebraic graph theory), such as how to characterise a new class of permutation groups that includes the primitive ones - the so called semiprimitive groups.