图的独立集数目在化学上称为Merrifield—Simmons指数,它是化学图论中应用比较广泛的拓扑指数之一.文献[2]得到n阶单圈图中具有最大、次大以及最小的Merrifield—Simmons指数的图类,以及讨论了当圈长的为k时具有最大Merrifield—Simmons指数的图.本文给出了圈长为k的n阶单圈图中第二大Merrifield—Simmons指数.
The number of independent sets of a graph is called the Merrifield - Simmons index of the graph in chemistry, and it is one of the most popular topological indices in chemical graph theory. A. Pedersen got the unicyclic graphs of oder n with the largest, the second largest and the smallest Merrifield - Simmons indices. In this paper, we give the unicyclic graph of oder n with the unique cycle length k and the second largest Merrifield - Simmons indices.