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Cindy (Sin Yi) Tsang
On the multiple holomorph of a finite almost simple group
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Published: |
September 20, 2019. |
Keywords: |
regular subgroups, holomorph and multiple holomorph, Hopf-Galois structures, almost simple groups. |
Subject: |
20B35, 20D05, 08A35. |
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Abstract
Let G be a group. Let Perm(G) denote its symmetric group and write Hol(G) for the normalizer of the subgroup of
left translations in Perm(G). The multiple holomorph NHol(G) of G is defined to be the normalizer of Hol(G) in Perm(G).
In this paper, we shall show that the quotient group NHol(G)/Hol(G) has order two whenever G is finite and almost simple. As an application of our techniques, we shall also develop a method to count the number of Hopf-Galois structures of isomorphic type on a finite almost simple field extension in terms of fixed point free endomorphisms. |
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Acknowledgements
The author would like to thank the referee for helpful comments.
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Author information
Cindy (Sin Yi) Tsang:
School of Mathematics (Zhuhai)
Sun Yat-Sen University
Zhuhai, Guangdong Province, China
zengshy26@mail.sysu.edu.cn
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