Abstract: For solving data redundancy and abnormal manipulation for XML documents in schema design under incomplete information circumstances, the normalization of XML Schema existing XML strong multivalucd dependencies under incomplete information circumstances was researched. hhe concepts of XML Schema and incomplete XML document tree according with XML Schema were formalized. Based on the equivalence of the sub-trees' information and the consistent of the sulrtrecs' information, XML strong multivalued dependencies' definition was given. Weak keys and XML strong multivalued dependencies weak normal form were given. The reasons of data redundancies aroused by XML Strong multivalued dependencies in XML Schema via the instance were analyzed, the transforming rules and the arithmetic of normalization were presented. The production in this work can deal with data redundancies in XML documents coming forth a great deal incomplete information and achieve better XML Schema design under incomplete information cmcumstances.

Key words: Incomplete information, Equivalence of the sulrtrecs' information, Consistent of the sulrtrecs' information XML strong multivalued dependencies,XML strong multivalued dependencies weak normal form