Generation of second maximal subgroups and the existence of special primes
File(s)
Author(s)
Liebeck, MW
Burness, TC
Shalev, A
Type
Journal Article
Abstract
Let G be a finite almost simple group. It is well known that G can be generated by three elements,
and in previous work we showed that 6 generators suffice for all maximal subgroups of G. In
this paper, we consider subgroups at the next level of the subgroup lattice—the so-called second
maximal subgroups. We prove that with the possible exception of some families of rank 1 groups
of Lie type, the number of generators of every second maximal subgroup of G is bounded by an
absolute constant. We also show that such a bound holds without any exceptions if and only if there
are only finitely many primes r for which there is a prime power q such that (q
r − 1)/(q − 1)
is prime. The latter statement is a formidable open problem in Number Theory. Applications to
random generation and polynomial growth are also given.
and in previous work we showed that 6 generators suffice for all maximal subgroups of G. In
this paper, we consider subgroups at the next level of the subgroup lattice—the so-called second
maximal subgroups. We prove that with the possible exception of some families of rank 1 groups
of Lie type, the number of generators of every second maximal subgroup of G is bounded by an
absolute constant. We also show that such a bound holds without any exceptions if and only if there
are only finitely many primes r for which there is a prime power q such that (q
r − 1)/(q − 1)
is prime. The latter statement is a formidable open problem in Number Theory. Applications to
random generation and polynomial growth are also given.
Date Issued
2017-11-07
Date Acceptance
2017-08-13
Citation
Forum of Mathematics, Sigma, 2017, 5
ISSN
2050-5094
Publisher
Cambridge University Press (CUP)
Journal / Book Title
Forum of Mathematics, Sigma
Volume
5
Copyright Statement
© The Author(s) 2017
This is an Open Access article, distributed under the terms of the Creative Commons Attribution licence (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted re-use, distribution, and reproduction in any medium, provided the original work is properly cited.
This is an Open Access article, distributed under the terms of the Creative Commons Attribution licence (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted re-use, distribution, and reproduction in any medium, provided the original work is properly cited.
License URL
Publication Status
Published
Article Number
e25