UKRAINIAN MATHEMATICAL JOURNAL, vol.66, no.7, pp.1028-1036, 2014 (SCI-Expanded)
We continue the study of modules over a general ring R whose submodules have a unique closure relative to a hereditary torsion theory on Mod-R. It is proved that, for a given ring R and a hereditary torsion theory tau on Mod-R, every submodule of every right R-module has a unique closure with respect to tau if and only if tau is generated by projective simple right R-modules. In particular, a ring R is a right Kasch ring if and only if every submodule of every right R-module has a unique closure with respect to the Lambek torsion theory.