TY - JOUR T1 - Finite Groups and the Sum of Orders of Their Subgroups AU - Lu , Jiakuan AU - Kuang , Meiqun AU - Wu , Kaixun AU - Zhang , Boru JO - Journal of Mathematical Study VL - 4 SP - 340 EP - 344 PY - 2023 DA - 2023/12 SN - 56 DO - http://doi.org/10.4208/jms.v56n4.23.02 UR - https://global-sci.org/intro/article_detail/jms/22253.html KW - Finite groups, Solvable groups, subgroup orders. AB -

Let $G$ be a finite group and $σ_1(G) = \frac{1}{|G|} ∑_{H≤G} |H|.$ In this paper, we prove that if $G$ is a nonsolvable group and $σ_1(G)=\frac{117}{ 20},$ then $G= A_5.$