Archiv der Mathematik ( IF 0.5 ) Pub Date : 2021-02-06 , DOI: 10.1007/s00013-020-01566-w Raimundo Bastos , Alex C. Dantas , Emerson de Melo
Let G be a group. The orbits of the natural action of \({{\,\mathrm{Aut}\,}}(G)\) on G are called automorphism orbits of G, and the number of automorphism orbits of G is denoted by \(\omega (G)\). Let G be a virtually nilpotent group such that \(\omega (G)< \infty \). We prove that \(G = K \rtimes H\) where H is a torsion subgroup and K is a torsion-free nilpotent radicable characteristic subgroup of G. Moreover, we prove that \(G^{'}= D \times {{\,\mathrm{Tor}\,}}(G^{'})\) where D is a torsion-free nilpotent radicable characteristic subgroup. In particular, if the maximum normal torsion subgroup \(\tau (G)\) of G is trivial, then \(G^{'}\) is nilpotent.
中文翻译:
自同构下具有有限个轨道的虚拟幂零群
令G为一组。\({{\,\ mathrm {Aut} \,}}(G)\)在G上的自然动作的轨道称为G的自同构轨道,而G的自同构轨道的数目由\(\ Ω(G)\)。令G是一个几乎为零的组,使得\(\ omega(G)<\ infty \)。我们证明\(G = K \ rtimes H \),其中H是G的扭转子群,K是G的无扭转幂等可辐照特征子群。此外,我们证明\(G ^ {'} = D \ times {{\,\ mathrm {Tor} \,}}(G ^ {'})\)其中D是无扭转幂等可装配特征子组。特别地,如果最大正常挠子群\(\ tau蛋白(G)\)的ģ是微不足道的,然后\(G ^ {'} \)是幂零。