Department of Mathematics, Taif University, P.O. Box 439, Hawiah 21974, Saudi Arabia
Copyright © 2012 S. Al-Nofayee. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
We generalize r-costar module to r-costar pair of contravariant functors between abelian categories.