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On the covering number of small symmetric groups and some sporadic simple groups

  • Luise-Charlotte Kappe , Daniela Nikolova-Popova and Eric Swartz ORCID logo EMAIL logo
Published/Copyright: October 12, 2016
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Abstract

A set of proper subgroups is a cover for a group if its union is the whole group. The minimal number of subgroups needed to cover G is called the covering number of G, denoted by σ(G). Determining σ(G) is an open problem for many nonsolvable groups. For symmetric groups Sn, Maróti determined σ(Sn) for odd n with the exception of n=9 and gave estimates for n even. In this paper we determine σ(Sn) for n=8,9,10,12. In addition we find the covering number for the Mathieu group M12 and improve an estimate given by Holmes for the Janko group J1.

Award Identifier / Grant number: DP120101336

Funding statement: The third author acknowledges the support of the Australian Research Council Discovery Grant DP120101336 during his time spent at The University of Western Australia.

Acknowledgements

We are very thankful to Eric Borenstein, the administrator of the High Performance Computing Initiative at Florida Atlantic University, for gaining us access to KoKo and for helping us implement Gurobi on KoKo, which included finding the best parameters for optimal performance. Finally, we would like to thank Gordon Royle for giving us access to his machine at The University of Western Australia.

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Received: 2016-2-17
Published Online: 2016-10-12
Published in Print: 2016-11-1

© 2016 by De Gruyter

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