Abreu指出“用代数连通度对树进行全排序仍然是个公开的问题”。同时,郭继明对树和连通图用代数连通度进行了排序。受到上述研究成果的启发,按照代数连通度从大到小的顺序确定双圈图的前五大值,以及达到这些值的图。
Abreu pointed out "finding a total ordering of trees by α (G) is a still open problem". Guo has ordered the trees and connected graphs by algebraic connectivity. Motivated by the above these ways and recent study on algebraic connectivity, the first fifth largest algebraic connectivity among all bicyclic graphs with n (n ≥ 22) vertices together with the corresponding graphs whose algebraic connectivity attain five values are determined.