关于子群均为特征子群的二秩无扭Abel群

On torsion free groups of rank 2 and in which all their subgroups are characteristic subgroups

利用Ｋｕｒǒｓ关于二秩无扭Ａｂｅｌ群的不变量理论和二元二次不定方程，给出了二秩无扭Ａｂｅｌ群的子群均为特征子群的充分必要条件．

On the basis of Kurǒs' complete system of invariants for torsion free groups and diaphantine equations,this paper investigates the structures of torsion free groups of rank 2 and in which all their subgroups are characteristic ones,also it gives necessary and sufficient conditions for these groups relative to their parameters.