GLASGOW MATHEMATICAL JOURNAL, vol.52, pp.261-269, 2010 (SCI-Expanded)
In this paper we introduce T-non-cosingular modules, dual Baer modules and K-modules. We prove that a module M is lifting and T-non-cosingular if and only if it is a dual Baer and K-module. Rings for which all modules are dual Baer are precisely determined. We also give a necessary condition for a finite direct sum of dual Baer modules to be dual Baer.