Document Type: Original Manuscript


Department of Mathematics, Fasa University, P.O.Box 74617-81189, Fasa, Iran.


In this paper the notion of Rees short exact sequence for S-posets
is introduced, and we investigate the conditions for which these sequences are left or right split. Unlike the case for S-acts,
being right split does not imply left split. Furthermore, we present
equivalent conditions of a right S-poset P for the functor Hom(P;-)
to be exact.