Representing and Understanding Discourse

The paper deals with understanding discourse. Its main goal is to function as in introductory course on the structure of discourse and text cohesion, of the type given by pronominal anaphora resolution, as it is seen today by many authors, but in many respects it also reflects a personal point of view. It begins with a presentation of centering theory (CT), a theory that explains the interaction between local coherence and choice of referring expressions. Some of its weak points are also revealed. Then it continues wit an insight into rhetorical structure theory (RST) a theory that accounts for the structure of texts in terms of relations that hold between parts of the text. Some of its numerous critics are also commented. Then a reconciliation between the two theories, with the benefit of extending the applicability of CT over difficult areas is proposed. This effort materialises in the development of an architecture of a system aimed at doing text interpretation. Representational issues are discussed rather detailed. Functioning of the model is detailed through the presentation of a worked example. Finally some considerations on a upper model (principle) for discourse interpretation are made. The treatment is rather introductory. It does not suppose any previous knowledge on discourse theories, but some bases in computational linguistics are beneficial