RelEx is an English-language semantic dependency relationship extractor, built on the Carnegie-Mellon Link Grammar parser. It can identify subject, object, indirect object, and many other syntactic dependency relationships between words in a sentence; it generates dependency trees, resembling those of dependency grammars, and specifically, those of Dekang Lin's MiniPar and the Stanford parser. It accomplishes this by applying a sequence of rules, based on the local context, and thus resembles constraint grammar in its implementation. In this sense, it implements some of the ideas of Hudson's Word Grammar. However, unlike other dependency parsers, RelEx attempts a greater degree of semantic normalization.
