短语词组短语torsion free group 非挠群torsion free commutative group 无扭交换群torsion -free abelian group 无扭阿贝尔群one -dimensional torsion group [数]一维挠群group without torsion 非挠群torsion radical of an l -group l群的挠根 返回 torsion group