In this paper the definitions of lower integral sum graph and the lower integral sum number of a graph are introduced,some properties of lower integral sum graphs are given,and it is proved that the lower integral sum number of complete tripartite graph K_ m,n,q (m,n,q≥2) is 2.
定义了下整和图与图的下整和数,给出下整和图的结构性质,并证明完全三部图Km,n,q(m,n,q≥2)的下整和数为2。
A graph G is said to be an lower integral sum graph if it is isomorphic to the lower integral sum graph of some SQ+.
一个图G称为下整和图,若它同构于某个S Q+的下整和图。
In this paper the definitions of lower integral sum graph and the lower integral sum number of a graph are introduced,some properties of lower integral sum graphs are given,and it is proved that the lower integral sum number of complete tripartite graph K_ m,n,q (m,n,q≥2) is 2.
定义了下整和图与图的下整和数,给出下整和图的结构性质,并证明完全三部图Km,n,q(m,n,q≥2)的下整和数为2。