Minimal non-abelian groups with an average condition on subgroups

Document Type : Research Paper

Authors

Department of Mathematical Sciences, Isfahan University of Technology, Isfahan 84156-83111‎, ‎Iran

Abstract

For a finite group $G$, the average order   $o(G)$   is defined to be the average of all order elements in $G$. We say that $G$ satisfies the average condition if $o(H)\leq o(G)$ for all subgroups $H$ of $G$. In [On a question of Jaikin-Zapirain about the average order elements of finite groups, Int. J. Group Theory, To appear] we proved that every abelian group satisfies the average condition. In this paper, we classify minimal non-abelian groups which satisfy the average condition.

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[1] Amiri H., & Jafarian Amiri S. M. (2011). Sum of element orders on  nite groups of the same order, J. Algebra Appl., 10(2), 187-190. https://doi.org/10.1109/VR.2006.148
[2] Amiri H., & Jafarian Amiri S. M. (2012). Sum of element orders of maximal subgroups of the symmetric group, Comm. Algebra, 40(2), 770-778. https://doi.org/10.1080/00927872.2010.537290
[3] Berkovich Y. (2008). Groups of prime power order, Vol. 1, Walter de Gruyter Berlin-New York.
[4] Chew C. Y., Chin A. Y. M., & Lim C. S. (2017). A recursive formula for the sum of element orders of  nite abelian groups, Results Math., 72, 1897-1905. https://doi.org/10.1007/s00025-017-0710-8
[5] Gorenstein D. (1980). Finite groups, Chelsea publishing company, New York.
[6] The GAP Group. Groups, Algorithms and Programing (2005). Version 4.4, (http://www.gap-system.org).
[7] Harrington J., Jones L., & Lamarche A. (2014). Characterizing  nite groups using the sum of the orders of the elements, Int. J. Combin., Article ID 835125, 8 pages. http://dx.doi.org/10.1155/2014/835125
[8] Herzog M., Longobardi P., & Maj M. (2018). An exact upper bound for sums of element orders in non-cyclic  nite groups, J. Pure Appl. Algebra, 222(7), 1628-1642. https://doi.org/10.1016/j.jpaa.2017.07.015
[9] Herzog M., Longobardi P., & Maj M. (2022). Another criterian for solvability of  nite groups, J. Algebra, 597, 1-23.  https://doi.org/10.1016/j.jalgebra.2022.01.005
[10] Herzog M., Longobardi P., & Maj M. (2023). On groups with average element orders equal to the average order of alternating group of degree 5, Glas. Mat., 58(2), 307-315. https://doi.org/10.3336/gm.58.2.10
[11] Jaikin-Zapirain A. (2011). On the number of conjugacy classes of  nite nilpotent groups, Adv. Math. 227(3), 1129-1143. https://doi.org/10.1016/j.aim.2011.02.021
[12] Khokhro E. I., Moreto A., & Zarrin M. (2021). The average element order and the number of conjugacy classes of  nite groups, J. Algebra, 569, 1-11. https://doi.org/10.1016/j.jalgebra.2020.11.009
[13] Miller G. A., & Moreno H. C. (1903). Non-abelian groups in which every subgroup is abelian, Trans. Amer. Math. Soc., 4(4), (1903) 398-404. https://doi.org/10.2307/1986409
[14] Tarnauceanu M. (2022). Another criterion for supersolvability of  nite groups, J. Algebra, 604, 682-693. https://doi.org/10.1016/j.jalgebra.2022.04.017
[15] Tarnauceanu M. (To appear). A caracterization of A5 by its average order, Int. J. Group Theory, http://dx.doi.org/10.22108//IJGT.2023.138637.1866
[16] Taeri B., & Tooshmalani Z. (To appear). On a question of Jaikin-Zapirain about the average order elements of  nite groups, Int. J. Group Theory, http://dx.doi.org/10.22108/IJGT.2024.139508.1879