ABSTRACT
Let R be a commutative ring and M an R‐module. Then M is a (weak) cancellation R-module if for ideals I and J of R, IM = JM implies I = J (I + 0 : M = J + 0 : M) and M is a restricted cancellation R-module if 0 ≠ IM = JM implies I = J. We study cancellation modules, weak cancellation modules, and restricted cancellation modules.
