Asymptotic enumeration of Cayley digraphs

In this paper we show that almost all Cayley digraphs have automorphism group as small as possible; that is, they are digraphical regular representations (DRRs). More precisely, we show that as r tends to infinity, for every finite group R of order r, out of all possible Cayley digraphs on R the proportion whose automorphism group is as small as possible tends to 1. This proves a natural conjecture first proposed in 1982 by Babai and Godsil.