刻画了具有次小、第三小Merrifield-Simmons指标的4叶树.具有r个悬挂点的树称为r叶树,所讨论的图均为简单和有限的无向图.
A Tree T is called a r-leaf-tree if T has r pendent vertices.Merrifield-Simmons index of 4-leaf-trees is investigated and the second and third minimal Merrifield-Simmons index of the trees with definite pendent vertices is characterized.