2019/07/03 by Marius Tărnăuceanu, Tărnăuceanu, Marius
Engineering · Mathematics · #Finite Group Theory Research #Graph theory and applications #graph theory and CDMA systems #math.GR
paper · pdf · doi:10.48550/arxiv.1907.02185
An error occurred in the proof of the main result. A new proof will be given as soon as possible
arxiv created 2019/08/11 · arxiv updated 2019/08/13
Let G be a finite group and σ1(G)=(1)/(|G|)∑H≤ G |H|. In this note, we prove that if σ1(G)<(117)/(20), then G is solvable. Moreover, we have σ1(G)=(117)/(20) if and only if G≅ A5. This solves an open problem posed in \cite8.