Let G = (V,E) be a simple graph without isolated vertices. For positive integer k, a 3-valued function f : V → {-1,0,1} is said to be a minus total k-subdominating function (MTkSF) if sum from (u∈N(v)) to f(u)≥1 fo...Let G = (V,E) be a simple graph without isolated vertices. For positive integer k, a 3-valued function f : V → {-1,0,1} is said to be a minus total k-subdominating function (MTkSF) if sum from (u∈N(v)) to f(u)≥1 for at least k vertices v in G, where N(v) is the open neighborhood of v. The minus total k-subdomination number γkt(G) equals the minimum weight of an MTkSF on G. In this paper, the values on the minus total k-subdomination number of some special graphs are investigated. Several lower bounds on γkt of general graphs and trees are obtained.展开更多
基金supported by the National Natural Science Foundation of China (Grant No.10571117)the Development Foundation of Shanghai Municipal Education Commission (Grant No.05AZ04)
文摘Let G = (V,E) be a simple graph without isolated vertices. For positive integer k, a 3-valued function f : V → {-1,0,1} is said to be a minus total k-subdominating function (MTkSF) if sum from (u∈N(v)) to f(u)≥1 for at least k vertices v in G, where N(v) is the open neighborhood of v. The minus total k-subdomination number γkt(G) equals the minimum weight of an MTkSF on G. In this paper, the values on the minus total k-subdomination number of some special graphs are investigated. Several lower bounds on γkt of general graphs and trees are obtained.
