循环ALCN-Tbox具有模型的条件

Condition of Cyclic ALCN-Tbox Exists Model

分析了带循环定义的描述逻辑系统ALCN的研究现状和存在的问题,研究了循环ALCN-Tbox具有模型的条件,指出了Baader文中命题2.9(LetTbe a terminology such that each cycle inGTcontains an even number ofnegative arcs.ThenTis monotone)的错误,并对该命题进行了修改,给出了循环ALCN-Tbox具有不动点模型(最小不动点模型和最大不动点模型)的条件.

The current research progresses and the existing problems of description logic system ALCN with terminological cycles are analyzed in this paper. The condition of cyclic ALCN-Tbox exists model is studied. The mistake of proposition 2.9 in the paper published by Baadr in 2003 （Let T be a terminology such that each cycle in GT contains an even number of negative arcs. Then T is monotone） is pointed out, also some modification of proposition 2.9 is given. The condition of cyclic ALCN-Tbox exists fixpoint models （lfp-model and gfp-model） is given.