Abstract The Petri net models of the clauses for logical inference using fixpoint are studied and the four-valued logic and the conflict transition concept are introduced.

• 逻辑推演是人工智能的基础之一；推演过程就是确定一个给定的命题是否由所收集的一组事实和子句规则所蕴含.；在推理研究中；已有多种模型方法来表示知识和推理过程