Head/modifier pairs for everyone

The “English Phrases for IR” (EP4IR) grammar is a grammar of English concentrating on the description of the noun phrase and the verb phrase. The grammar is provided with a large lexicon, providing detailed Part-Of-Speech information. It is quite robust against badly formed input and unknown words and generates only the most probable analysis. The EP4IR grammar and lexicon are released along with the AGFL system [1], which is the first parser-generator for linguistic applications available under the GNU Public License. The parsers generated from it fall under the LGPL, so that they can be used for scientific and even commercial applications. From the EP4IR grammar and lexicon, an English parser can be generated automatically using the AGFL system, which produces as its output not parse trees but Head/ Modifier trees, binary dependency trees that can be unnested to Head/Modifier pairs. In this transduction process, the HM trees are syntactically normalized. The pairs generated when parsing some text represent only the major relations expressed in the text [2]: