Nested logic programs with ordered disjunction

In this paper we define a class of nested logic programs, nested logic programs with ordered disjunction (LPODs+), which allows to specify qualitative preferences by means of nested preference expressions. For doing this we extend the syntax of logic programs with ordered disjunction (LPODs) to capture more general expressions. We define the LPODs+ semantics in a simple way and we extend most of the results of logic programs with ordered disjunction showing how our approach effectively is a proper generalisation of LPODs.