2006/05/30 by James P. Cossey, Cossey, James P.
Mathematics · #20C15 #20C20 #FOS: Mathematics #Group Theory (math.GR) #Representation Theory (math.RT) #math.GR #math.RT #msc:20C15 #msc:20C20
paper · pdf · doi:10.48550/arxiv.math/0605772
arxiv created 2006/05/30 · arxiv updated 2009/12/01
The Fong-Swan theorem shows that for a p-solvable group G and Brauer character ϕ∈ \ibrg, there is an ordinary character χ∈ \irrg such that χ0 = ϕ, where 0 denotes restriction to the p-regular elements of G. This still holds in the generality of π-separable groups \citebpi, where \ibrg is replaced by \ipig. For ϕ∈ \ipig, let Lϕ = \χ∈ \irrg | χ0 = ϕ\. In this paper we give a lower bound for the size of Lϕ in terms of the structure of the normal nucleus of ϕ and, if G is assumed to be odd and π= \p' \, we give an upper bound for Lϕ in terms of the vertex subgroup for ϕ.