Aggregation and negation-as-failure

Thr problem of expressing partial-order programs via negation-as-failure (NF), a well-known non-monotonic operation in logic programming, is considered. Any cost-monotonic partial-order program P is translated to a stratified normal program such as the stratified semantics of the translated program. The ability to effect such a translation is significant because the resulting normal programs do not make any explicit use of the aggregation capability, yet they are concise and intuitive. The success of this translation is due to the fact that the translated program is a stratified normal program.