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 works and the existing problems of terminological cycles in description logics are analyzed in this paper. Referring to the works of Baader F and Nebel B,we aim in a new direction. Firstly,description logic νL is defined,and the description graphs GT and GJ are redefined. A syntax condition for the satisfiability of membership relation is given. By using this syntax condition,we prove the following:The subsumption reasoning in νL with respect to gfp-model,lfp-model and descriptive model is polynomial.
