Geodesics and almost geodesic cycles in random regular graphs
✍ Scribed by Itai Benjamini; Carlos Hoppen; Eran Ofek; Paweł Prałat; Nick Wormald
- Publisher
- John Wiley and Sons
- Year
- 2010
- Tongue
- English
- Weight
- 198 KB
- Volume
- 66
- Category
- Article
- ISSN
- 0364-9024
No coin nor oath required. For personal study only.
✦ Synopsis
A geodesic in a graph G is a shortest path between two vertices of G. For a specific function e(n) of n, we define an almost geodesic cycle C in G to be a cycle in which for every two vertices u and v in C, the distance d G (u, v) is at least d C (u, v)-e(n). Let (n) be any function tending to infinity with n. We consider a random d-regular graph on n vertices. We show that almost all pairs of vertices belong to an almost geodesic cycle C with e(n) = log d-1 log d-1 n+ (n) and |C| = 2 log d-1 n+O( (n)). Along the way, we obtain results on near-geodesic paths. We also give the limiting distribution of the number of geodesics between two random vertices in this random graph.
📜 SIMILAR VOLUMES
Let G be chosen uniformly at random from the set G G r, n of r-regular graphs w x Ž . with vertex set n . We describe polynomial time algorithms that whp i find a Ž . Hamilton cycle in G, and ii approximately count the number of Hamilton cycles in G.
The asymptotic distribution of the number of cycles of length l in a random r-regular graph is determined. The length of the cycles is defined as a function of the Ž . Ž . number of vertices n, thus l s l n , and the length satisfies l n ª ϱ as n ª ϱ. The limiting Ž . Ž . distribution turns out to
## UNIVERSIW OF WATERLOO ' The research reported here has been sponsored by the Canadian Commonwealth Association.
Select four perfect matchings of 2n vertices, independently at random. We find the asymptotic probability that each of the first and second matchings forms a Hamilton cycle with each of the third and fourth. This is generalised to embrace any fixed number of perfect matchings, where a prescribed set