A well known theorem of R. Baer states that if G is a group and G/Z(n)(G) is finite, then gamma(n+1)(G) is finite. In this article, we extend this theorem for groups G that have subgroups A of Aut(G) such that A/Inn(G) is finitely generated or is of finite special rank. Furthermore, some new upper bounds for vertical bar gamma(n+1)(G)vertical bar and vertical bar gamma(n+1)(G, A)vertical bar are presented.
机构:
Univ Paris, IMJ, PRG, UMR 7586, Batiment Sophie Germain Case 7012, F-75205 Paris 13, FranceUniv Paris, IMJ, PRG, UMR 7586, Batiment Sophie Germain Case 7012, F-75205 Paris 13, France
机构:
Huaiyin Normal Univ, Sch Math Sci, Huaian 223300, Jiangsu, Peoples R ChinaHuaiyin Normal Univ, Sch Math Sci, Huaian 223300, Jiangsu, Peoples R China