On coprime G-conjugacy class sizes in a normal subgroup

2014 ◽  
Vol 30 (9) ◽  
pp. 1588-1594 ◽  
Author(s):  
Xian He Zhao ◽  
Hai Peng Qu ◽  
Gui Yun Chen
2011 ◽  
Vol 121 (4) ◽  
pp. 397-404 ◽  
Author(s):  
XIANHE ZHAO ◽  
GUIYUN CHEN ◽  
JIAOYUN SHI

2016 ◽  
Vol 15 (08) ◽  
pp. 1650151
Author(s):  
Changguo Shao ◽  
Qinhui Jiang

Let [Formula: see text] be a group and [Formula: see text] be a normal subgroup of [Formula: see text]. If the set [Formula: see text] is composed by consecutive integers, then [Formula: see text] is either nilpotent or a quasi-Frobenius group with abelian kernel and complements. This is a generalization of Theorem 2 of [A. Beltrán, M. J. Felipe and C. G. Shao, [Formula: see text]-divisibility of conjugacy class sizes and normal [Formula: see text]-complements, J. Group Theory 18 (2015) 133–141].


Filomat ◽  
2020 ◽  
Vol 34 (5) ◽  
pp. 1713-1719
Author(s):  
Neda Ahanjideh

For a finite group G, let Z(G) denote the center of G and cs*(G) be the set of non-trivial conjugacy class sizes of G. In this paper, we show that if G is a finite group such that for some odd prime power q ? 4, cs*(G) = cs*(PGL2(q)), then either G ? PGL2(q) X Z(G) or G contains a normal subgroup N and a non-trivial element t ? G such that N ? PSL2(q)X Z(G), t2 ? N and G = N. ?t?. This shows that the almost simple groups cannot be determined by their set of conjugacy class sizes (up to an abelian direct factor).


Author(s):  
SH. RAHIMI ◽  
Z. AKHLAGHI

Abstract Given a finite group G with a normal subgroup N, the simple graph $\Gamma _{\textit {G}}( \textit {N} )$ is a graph whose vertices are of the form $|x^G|$ , where $x\in {N\setminus {Z(G)}}$ and $x^G$ is the G-conjugacy class of N containing the element x. Two vertices $|x^G|$ and $|y^G|$ are adjacent if they are not coprime. We prove that, if $\Gamma _G(N)$ is a connected incomplete regular graph, then $N= P \times {A}$ where P is a p-group, for some prime p, $A\leq {Z(G)}$ and $\textbf {Z}(N)\not = N\cap \textbf {Z}(G)$ .


2015 ◽  
Vol 43 (8) ◽  
pp. 3365-3371 ◽  
Author(s):  
Yang Liu ◽  
Ziqun Lu

1996 ◽  
Vol 39 (3) ◽  
pp. 346-351 ◽  
Author(s):  
Mary K. Marshall

AbstractAn A-group is a finite solvable group all of whose Sylow subgroups are abelian. In this paper, we are interested in bounding the derived length of an A-group G as a function of the number of distinct sizes of the conjugacy classes of G. Although we do not find a specific bound of this type, we do prove that such a bound exists. We also prove that if G is an A-group with a faithful and completely reducible G-module V, then the derived length of G is bounded by a function of the number of distinct orbit sizes under the action of G on V.


2012 ◽  
Vol 57 (1) ◽  
Author(s):  
SHEILA ILANGOVAN ◽  
NOR HANIZA SARMIN

Dalam kertas ini, kita menyelidik ciri tak terturunkan dan panjang kelas konjugat bagi kumpulan–2 berpenjana–2 dengan kelas nilpoten 2. Panjang kelas konjugat bagi elemen x dalam kumpulan G adalah peringkat xG di mana xG ialah kelas konjugat yang mengandungi x. Kajian ini adalah berdasarkan pada klasifikasi kumpulan yang diberikan oleh Magidin pada tahun 2006. Kita akan membuktikan bahawa panjang kelas konjugat bagi G ialah 2ρ di mana 0 <= ρ <= γdan |G'| = 2γ.


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