The $p$-nilpotency of finite groups with some weakly pronormal subgroups.
(English).Czechoslovak Mathematical Journal,
vol. 70
(2020),
issue 3,
pp. 805-816
Summary: For a finite group $G$ and a fixed Sylow $p$-subgroup $P$ of $G$, Ballester-Bolinches and Guo proved in 2000 that $G$ is $p$-nilpotent if every element of $P\cap G'$ with order $p$ lies in the center of $N_G(P)$ and when $p=2$, either every element of $P\cap G'$ with order $4$ lies in the center of $N_G(P)$ or $P$ is quaternion-free and $N_G(P)$ is $2$-nilpotent. Asaad introduced weakly pronormal subgroup of $G$ in 2014 and proved that $G$ is $p$-nilpotent if every element of $P$ with order $p$ is weakly pronormal in $G$ and when $p=2$, every element of $P$ with order $4$ is also weakly pronormal in $G$. These results generalized famous Itô's Lemma. We are motivated to generalize Ballester-Bolinches and Guo's Theorem and Asaad's Theorem. It is proved that if $p$ is the smallest prime dividing the order of a group $G$ and $P$, a Sylow $p$-subgroup of $G$, then $G$ is $p$-nilpotent if $G$ is $S_4$-free and every subgroup of order $p$ in $P\cap P^x\cap G^{\mathfrak {N_p}}$ is weakly pronormal in $N_G(P)$ for all $x\in G\setminus N_G(P)$, and when $p=2$, $P$ is quaternion-free, where $G^{\mathfrak {N_p}}$ is the $p$-nilpotent residual of $G$.
[4] Ballester-Bolinches, A.: $\mathfrak H$-normalizers and local definitions of saturated formations of finite groups. Isr. J. Math. 67 (1989), 312-326. DOI 10.1007/BF02764949 | MR 1029905 | Zbl 0689.20036
[5] Ballester-Bolinches, A., Beidleman, J. C., Feldman, A. D., Ragland, M. F.: On generalised pronormal subgroups of finite groups. Glasg. Math. J. 56 (2014), 691-703. DOI 10.1017/S0017089514000159 | MR 3250272 | Zbl 1322.20011
[6] Ballester-Bolinches, A., Beidleman, J. C., Feldman, A. D., Ragland, M. F.: Finite groups in which pronormality and $\mathfrak F$-pronormality coincide. J. Group Theory 19 (2016), 323-329. DOI 10.1515/jgth-2015-0035 | MR 3466598 | Zbl 1344.20027
[15] Guo, X., Shum, K. P.: Permutability of minimal subgroups and $p$-nilpotentcy of finite groups. Isr. J. Math. 136 (2003), 145-155. DOI 10.1007/BF02807195 | MR 1998107 | Zbl 1048.20005