A.: Logic Wrappers and XSLT Transformations for Tuples Extraction from HTML

Abstract. Recently it was shown that existing general-purpose inductive logic programming systems are useful for learning wrappers (known as L-wrappers) to extract data from HTML documents. Here we propose a formalization of L-wrappers and their patterns, including their syntax and semantics and related properties and operations. A mapping of the patterns to a subset of XSLT that has a formal semantics is outlined and demonstrated by an example. The mapping actually shows how the theory can be applied to obtain efficient wrappers for information extraction from HTML.