In 1975, John Sheehan conjectured that every Hamiltonian 4-regular graph has a second Hamiltonian cycle. Combined with earlier results this would imply that every Hamiltonian r-regular graph (r 3) has a second Hamiltonian cycle. We shall verify this for r 300.
Independent domination in regular graphs
โ Scribed by Julie Haviland
- Publisher
- Elsevier Science
- Year
- 1995
- Tongue
- English
- Weight
- 387 KB
- Volume
- 143
- Category
- Article
- ISSN
- 0012-365X
No coin nor oath required. For personal study only.
โฆ Synopsis
Let G be a simple graph of order n. The independent domination number i(G) is defined to be the minimum cardinality among all maximal independent sets of vertices of G. Motivated by work of Cockayne et al. (1991) and Cockayne and Mynhardt (1989), we investigate the maximum value of the product of the independent domination numbers of a graph and its complement, as a function of n. In particular we prove that if G is regular then i(G). i(G) < (n + 14)2/12.68.
๐ SIMILAR VOLUMES
In answer to the open questions proposed by Henning and Slater, we give sharp upper bounds on the upper signed domination number of a regular graph and on the signed domination number of a connected cubic graph. Let G = (V, E) be a simple graph. For v E V, we denote by d(u) the degree of v in V, by
We show that for each k L 4 there exists a connected k-domination critical graph with independent domination number exceeding k, thus disproving a conjecture of Sumner and Blitch ( J Cornbinatorial Theory B 34 (19831, 65-76) in all cases except k = 3.