A Tree-like Knowledge Base Revision Algorithm
一类树型知识库的更新算法

Knowledge base revision is to add new knowledge into the knowledge base, and to delete old knowledge if it is necessary for preserving consistency. The recently proposed knowledge base revision methods are all intractable in general case. By restricting the structure of the knowledge base, a polynomial revision algorithm is given in this paper when the corresponding constraint graph of the knowledge base is a tree. In the constraint tree, the authors use a bottom-up process to get the revision knowledge base.