Computing character degrees via a Galois connection

In a previous paper, the second author established that, given finite fields F<E and certain subgroups C≤E × , there is a Galois connection between the intermediate field lattice {L∣F≤L≤E} and C 's subgroup lattice. Based on the Galois connection, the paper then calculated the irreducible...

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Main Authors: Mark L. Lewis, John K. McVey
Format: Article
Language:English
Published: University of Isfahan 2015-03-01
Series:International Journal of Group Theory
Subjects:
Online Access:http://www.theoryofgroups.ir/pdf_6212_edb9e19829eb4a1d2264f3c3f26089ed.html
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author Mark L. Lewis
John K. McVey
author_facet Mark L. Lewis
John K. McVey
author_sort Mark L. Lewis
collection DOAJ
description In a previous paper, the second author established that, given finite fields F<E and certain subgroups C≤E × , there is a Galois connection between the intermediate field lattice {L∣F≤L≤E} and C 's subgroup lattice. Based on the Galois connection, the paper then calculated the irreducible, complex character degrees of the semi-direct product C⋊Gal(E/F) . However, the analysis when |F| is a Mersenne prime is more complicated, so certain cases were omitted from that paper. The present exposition, which is a reworking of the previous article, provides a uniform analysis over all the families, including the previously undetermined ones. In the group C⋊Gal(E/F) , we use the Galois connection to calculate stabilizers of linear characters, and these stabilizers determine the full character degree set. This is shown for each subgroup C≤E × which satisfies the condition that every prime dividing |E × :C| divides |F × | .
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spelling doaj.art-2c935013ffd449e6b00c1904c1ed6fc42022-12-22T00:32:22ZengUniversity of IsfahanInternational Journal of Group Theory2251-76502251-76692015-03-014116Computing character degrees via a Galois connectionMark L. Lewis 0John K. McVey 1Department of Mathematical Sciences Kent State UniversityDepartment of Mathematical Sciences Kent State UniversityIn a previous paper, the second author established that, given finite fields F<E and certain subgroups C≤E × , there is a Galois connection between the intermediate field lattice {L∣F≤L≤E} and C 's subgroup lattice. Based on the Galois connection, the paper then calculated the irreducible, complex character degrees of the semi-direct product C⋊Gal(E/F) . However, the analysis when |F| is a Mersenne prime is more complicated, so certain cases were omitted from that paper. The present exposition, which is a reworking of the previous article, provides a uniform analysis over all the families, including the previously undetermined ones. In the group C⋊Gal(E/F) , we use the Galois connection to calculate stabilizers of linear characters, and these stabilizers determine the full character degree set. This is shown for each subgroup C≤E × which satisfies the condition that every prime dividing |E × :C| divides |F × | .http://www.theoryofgroups.ir/pdf_6212_edb9e19829eb4a1d2264f3c3f26089ed.htmlGalois correspondencelatticecharacter degreefinite field
spellingShingle Mark L. Lewis
John K. McVey
Computing character degrees via a Galois connection
International Journal of Group Theory
Galois correspondence
lattice
character degree
finite field
title Computing character degrees via a Galois connection
title_full Computing character degrees via a Galois connection
title_fullStr Computing character degrees via a Galois connection
title_full_unstemmed Computing character degrees via a Galois connection
title_short Computing character degrees via a Galois connection
title_sort computing character degrees via a galois connection
topic Galois correspondence
lattice
character degree
finite field
url http://www.theoryofgroups.ir/pdf_6212_edb9e19829eb4a1d2264f3c3f26089ed.html
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