Lower bounds on the minus domination and k-subdomination numbers
β Scribed by Liying Kang; Hong Qiao; Erfang Shan; Dingzhu Du
- Publisher
- Elsevier Science
- Year
- 2003
- Tongue
- English
- Weight
- 118 KB
- Volume
- 296
- Category
- Article
- ISSN
- 0304-3975
No coin nor oath required. For personal study only.
β¦ Synopsis
A three-valued function f deΓΏned on the vertex set of a graph G = (V; E), f : V β {-1; 0; 1} is a minus dominating function if the sum of its function values over any closed neighborhood is at least one. That is, for every
consists of v and all vertices adjacent to v. The weight of a minus function is f(V ) = vβV f(v). The minus domination number of a graph G, denoted by -(G), equals the minimum weight of a minus dominating function of G. In this paper, sharp lower bounds on minus domination of a bipartite graph are given. Thus, we prove a conjecture proposed by Dunbar et al. (Discrete Math. 199 (1999) 35), and we give a lower bound on ks (G) of a graph G.
π SIMILAR VOLUMES
Let G be a graph with n vertices. The mean color number of G, denoted by (G), is the average number of colors used in all n-colorings of G. This paper proves that (G) ! (Q), where Q is any 2-tree with n vertices and G is any graph whose vertex set has an ordering x 1 ,x 2 , . . . ,x n such that x i
If a graph G with cycle rank p contains both spanning trees with rn and with n end-vertices, rn < n, then G has at least 2p spanning trees with k end-vertices for each integer k, rn < k < n. Moreover, the lower bound of 2p is best possible. [ l ] and Schuster [4] independently proved that such span
## Abstract Graph __G__ is a (__k__,β__p__)βgraph if __G__ does not contain a complete graph on __k__ vertices __K__~__k__~, nor an independent set of order __p__. Given a (__k__,β__p__)βgraph __G__ and a (__k__,β__q__)βgraph __H__, such that __G__ and __H__ contain an induced subgraph isomorphic t