Character expansiveness in finite groups

We say that a finite group $G$ is conjugacy expansive if for anynormal subset $S$ and any conjugacy class $C$ of $G$ the normalset $SC$ consists of at least as many conjugacy classes of $G$ as$S$ does. Halasi, Mar'oti, Sidki, Bezerra have shown that a groupis conjugacy expansive if and only if...

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Bibliographic Details
Main Authors: Attila Maroti, Franciska Petenyi, Zoltan Halasi
Format: Article
Language:English
Published: University of Isfahan 2013-06-01
Series:International Journal of Group Theory
Subjects:
Online Access:http://www.theoryofgroups.ir/?_action=showPDF&article=1660&_ob=4335a14289e50a35e7186085ea9a408c&fileName=full_text.pdf
Description
Summary:We say that a finite group $G$ is conjugacy expansive if for anynormal subset $S$ and any conjugacy class $C$ of $G$ the normalset $SC$ consists of at least as many conjugacy classes of $G$ as$S$ does. Halasi, Mar'oti, Sidki, Bezerra have shown that a groupis conjugacy expansive if and only if it is a direct product ofconjugacy expansive simple or abelian groups.By considering a character analogue of the above, we say that afinite group $G$ is character expansive if for any complexcharacter $alpha$ and irreducible character $chi$ of $G$ thecharacter $alpha chi$ has at least as many irreducibleconstituents, counting without multiplicity, as $alpha$ does. Inthis paper we take some initial steps in determining characterexpansive groups.
ISSN:2251-7650
2251-7669