“…Object-orientation has gained much attention in the comnmnity of logic programming [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20]. The objectoriented logic programming (OOLP) systems which properly combine logic programming with object-oriented programming, not only support the features of both paradigms, such as modularity, information hiding, inheritance, and high expressive power, but also enrich the notions of traditional objects, such as incomplete objects I ll.bi-directional message passing, flexible inter-object nondetcmfism [2] and non-monotonic inheritance.…”