Identifying Assertions in Text and Discourse: The Presentational Relative Clause Construction

In this paper we investigate the Presentational Relative Clause (PRC) construction. In both the linguistic and NLP literature, relative clauses have been considered to contain background information that is not directly relevant or highly useful in semantic analysis. In text summarization in particular, the information contained in the relative clauses is often removed, being viewed as non-central content to the topic or discourse. We discuss the importance of distinguishing the PRC construction from other relative clause types. We show that in the PRC, the relative clause, rather than the main clause, contains the assertion of the utterance. Based on linguistic analysis, we suggest informative features that may be used in automatic extraction of PRC constructions. We believe that identifying this construction will be useful in discriminating central information from peripheral.