Brian Lowe, J. Zobel, and Ron Sacks-Davis
Most documents have a hierarchical structure, which can be made explicit by markup languages such as SGML. In this paper we propose a formal model for representation of hierarchically structured documents, to be used as the basis for document query languages. The model uses a redundant representation of the document elements to simplify the expression of common queries. As an illustration of the power of the model we show how queries might be expressed, both as set-theoretic expressions and in a simple algebra, and outline how queries might be evaluated in a practical system.