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A pronormality criterion for supplements to abelian normal subgroups. / Kondrat’ev, A. S.; Maslova, N. V.; Revin, D. O.
In: Proceedings of the Steklov Institute of Mathematics, Vol. 296, No. 1, 01.04.2017, p. 145-150.Research output: Contribution to journal › Article › peer-review
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TY - JOUR
T1 - A pronormality criterion for supplements to abelian normal subgroups
AU - Kondrat’ev, A. S.
AU - Maslova, N. V.
AU - Revin, D. O.
PY - 2017/4/1
Y1 - 2017/4/1
N2 - A subgroup H of a group G is called pronormal if, for any element g ∈ G, the subgroups H and Hg are conjugate in the subgroup <H,Hg>. We prove that, if a group G has a normal abelian subgroup V and a subgroup H such that G = HV, then H is pronormal in G if and only if U = NU(H)[H,U] for any H-invariant subgroup U of V. Using this fact, we prove that the simple symplectic group PSp6n(q) with q ≡ ±3 (mod 8) contains a nonpronormal subgroup of odd index. Hence, we disprove the conjecture on the pronormality of subgroups of odd indices in finite simple groups, which was formulated in 2012 by E.P. Vdovin and D.O. Revin and verified by the authors in 2015 for many families of simple finite groups.
AB - A subgroup H of a group G is called pronormal if, for any element g ∈ G, the subgroups H and Hg are conjugate in the subgroup <H,Hg>. We prove that, if a group G has a normal abelian subgroup V and a subgroup H such that G = HV, then H is pronormal in G if and only if U = NU(H)[H,U] for any H-invariant subgroup U of V. Using this fact, we prove that the simple symplectic group PSp6n(q) with q ≡ ±3 (mod 8) contains a nonpronormal subgroup of odd index. Hence, we disprove the conjecture on the pronormality of subgroups of odd indices in finite simple groups, which was formulated in 2012 by E.P. Vdovin and D.O. Revin and verified by the authors in 2015 for many families of simple finite groups.
KW - complement of a subgroup
KW - finite simple group
KW - pronormal subgroup
KW - subgroup of odd index
KW - supplement of a subgroup
KW - FINITE SIMPLE-GROUPS
KW - ODD INDEX
UR - http://www.scopus.com/inward/record.url?scp=85018776312&partnerID=8YFLogxK
U2 - 10.1134/S0081543817020134
DO - 10.1134/S0081543817020134
M3 - Article
AN - SCOPUS:85018776312
VL - 296
SP - 145
EP - 150
JO - Proceedings of the Steklov Institute of Mathematics
JF - Proceedings of the Steklov Institute of Mathematics
SN - 0081-5438
IS - 1
ER -
ID: 10036713