3. The moving right frontier
This paper analyzes systematic cases of revision of the discourse structure entailing a modification of the right frontier. We show that the coordinating or subordinating nature of discourse relations plays a major role in this revision, examining in particular a relation typical in narratives, <i>Result</i>, as well as a family of dialog relations: content-relations introduced by interrogatives. Their complex behaviour shows that the Right Frontier Constraint, a major principle in most discourse theories, needs to be handled with care. We also generalize the discussion about problems due to the multiplication and the sophistication of discourse principles operating within SDRT, in particular the Maximize Discourse Coherence principle which constitutes an important improvement of the theory but also introduces some methodological issues.