  Understanding how torsion theories are described and constructed is crucial
to the study of torsion theory. Mutations of torsion theories have been studied
as a method of constructing another torsion theory from a given one. We have
already obtained how to mutate ordinary torsion theories into generalized
torsion theories associated with a Serre subcategory. The paper investigates
when the generalized torsion theories give ordinary torsion theories and when
ordinary torsion theories provide each other.
