Abstract: To solve the logical implication problem of Extensible Markup Language (XML) weak functional dependency under incomplete information circumstances, the weak functional dependency and inference rules for XML based on XML Schema were discussed. The concepts of XML Schema and incomplete XML document tree conforming to XML Schema were formalized. Based on the concepts of subtree information equivalence and subtree information consistency, the definition of XML weak functional dependency was given and its properties were studied. A set of inference rules for XML weak functional dependency was presented and its soundness and completeness were given. This work is foundation of normalizing XML Schema with XML weak functional dependency under incomplete information circumstances.

Key words: subtree information consistency, subtree information equivalence, Extensible Markup Language (XML) weak functional dependency, inference rule

摘要： 为了解决不完全信息环境下可扩展标记语言(XML)弱函数依赖的逻辑蕴涵问题，基于XML Schema研究了XML弱函数依赖及其推理规则。给出了XML Schema、符合XML Schema的不完全XML文档树等概念；基于子树信息等价、子树信息相容的概念提出了XML弱函数依赖的定义和性质；提出了相应的推理规则集，并对其正确性和完备性进行了证明。为不完全信息环境下存在XML弱函数依赖的XML Schema规范化的研究奠定了基础。

关键词: 子树信息相容, 子树信息等价, XML弱函数依赖, 推理规则