Asymptotic enumeration of sparse graphs with a minimum degree constraint

We derive an asymptotic formula for the number of graphs with n vertices all of degree at least k, and m edges, with k fixed. This is done by summing the asymptotic formula for the number of graphs with a given degree sequence, all degrees at least k. This approach requires analysis of a set of independent truncated Poisson variables, which approximate the degree sequence of a random graph chosen uniformly at random among all graphs with n vertices, m edges, and a minimum degree at least k. Our main result generalizes a result of Bender, Canfield and McKay and of Korshunov, who treated the case k = 1 using different methods. (C) 2003 Elsevier Science (USA). All rights reserved.