Reflection Subquotients of Unitary Reflection Groups
Canadian journal of mathematics, Tome 51 (1999) no. 6, pp. 1175-1193

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Let $G$ be a finite group generated by (pseudo-) reflections in a complex vector space and let $g$ be any linear transformation which normalises $G$ . In an earlier paper, the authors showed how to associate with any maximal eigenspace of an element of the coset $gG$ , a subquotient of $G$ which acts as a reflection group on the eigenspace. In this work, we address the questions of irreducibility and the coexponents of this subquotient, as well as centralisers in $G$ of certain elements of the coset. A criterion is also given in terms of the invariant degrees of $G$ for an integer to be regular for $G$ . A key tool is the investigation of extensions of invariant vector fields on the eigenspace, which leads to some results and questions concerning the geometry of intersections of invariant hypersurfaces.
DOI : 10.4153/CJM-1999-052-4
Mots-clés : 51F15, 20H15, 20G40, 20F55, 14C17
Lehrer, G. I.; Springer, T. A. Reflection Subquotients of Unitary Reflection Groups. Canadian journal of mathematics, Tome 51 (1999) no. 6, pp. 1175-1193. doi: 10.4153/CJM-1999-052-4
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     year = {1999},
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     url = {http://geodesic.mathdoc.fr/articles/10.4153/CJM-1999-052-4/}
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