A light but formal introduction to XQuery

We give a light-weight but formal introduction to XQuery by defining a sublanguage of XQuery. We ignore typing, and don t consider namespaces, comments, programming instructions, and entities. To avoid confusion we call our version LiXQuery (Light XQuery). LiXQuery is fully downwards compatible with XQuery. Its syntax and its semantics are far less complex than that of XQuery, but the typical expressions of XQuery are included in LiXQuery. We claim that LiXQuery is an elegant and simple sublanguage of XQuery that can be used for educational and research purposes. We give the complete syntax and the formal semantics of LiXQuery.