@article {IOPORT.05909466,
    author       = {Chen, Yin and Lin, Fangzhen and Zhang, Yan and Zhou, Yi},
    title        = {Loop-separable programs and their first-order definability.},
    year         = {2011},
    journal      = {Artificial Intelligence},
    volume       = {175},
    number       = {3-4},
    issn         = {0004-3702},
    pages        = {890-913},
    publisher    = {Elsevier Science Publishers, Amsterdam},
    doi          = {10.1016/j.artint.2010.12.001},
    abstract     = {Summary: An answer set program with variables is first-order definable on finite structures if the set of its finite answer sets can be captured by a first-order sentence. Characterizing classes of programs that are first-order definable on finite structures is theoretically challenging and of practical relevance to answer set programming. In this paper, we identify a non-trivial class of answer set programs called loop-separable programs and show that they are first-order definable on finite structures.},
    identifier   = {05909466},
}