短语词组短語torsion free group 非撓群torsion free commutative group 無扭交換群torsion -free abelian group 無扭阿貝爾群one -dimensional torsion group [數]一維撓群group without torsion 非撓群torsion radical of an l -group l群的撓根 返回 torsion group