2011/12/26 by Acciarri, Cristina, Shumyatsky, Pavel · 1 citation
#20E18 #20F50 #FOS: Mathematics #Group Theory (math.GR)
paper · doi:10.48550/arxiv.1112.5879
For a family of group words w we show that if G is a profinite group in which all w-values are contained in a union of finitely many subgroups with a prescribed property, then w(G) has the same property as well. In particular, we show this in the case where the subgroups are periodic or of finite rank. If G contains finitely many subgroups G1,G2,...,Gs of finite exponent e whose union contains all γk-values in G, it is shown that γk(G) has finite (e,k,s)-bounded exponent. If G contains finitely many subgroups G1,G2,...,Gs of finite rank r whose union contains all γk-values, it is shown that γk(G) has finite (k,r,s)-bounded rank.