Title
Longest cycles in sparse random digraphs.
Abstract
Long paths and cycles in sparse random graphs and digraphs were studied intensively in the 1980's. It was finally shown by Frieze in 1986 that the random graph G(n, p) with p = c/n has a cycle on at all but at most (1+epsilon)ce(-c)n vertices with high probability, where epsilon = epsilon(c) -> 0 as c -> infinity. This estimate on the number of uncovered vertices is essentially tight due to vertices of degree 1. However, for the random digraph D(n, p) no tight result was known and the best estimate was a factor of c/2 away from the corresponding lower bound. In this work we close this gap and show that the random digraph D(n, p) with p = c/n has a cycle containing all but (2 + epsilon)e(-c)n vertices w.h.p., where epsilon = epsilon(c) -> 0 as c -> infinity. This is essentially tight since w.h.p. such a random digraph contains (2e(-c) -o(1))n vertices with zero in-degree or out-degree. (C) 2012 Wiley Periodicals, Inc. Random Struct. Alg., 43, 1-15, 2013
Year
DOI
Venue
2013
10.1002/rsa.20435
RANDOM STRUCTURES & ALGORITHMS
Keywords
Field
DocType
directed graphs,random graphs,cycles
Random regular graph,Discrete mathematics,Combinatorics,Random graph,Vertex (geometry),Upper and lower bounds,struct,Directed graph,Digraph,Mathematics
Journal
Volume
Issue
ISSN
43.0
1.0
1042-9832
Citations 
PageRank 
References 
3
0.54
6
Authors
3
Name
Order
Citations
PageRank
michael krivelevich11688179.90
Eyal Lubetzky235528.87
Benny Sudakov31391159.71