Abstract
Synchronized multimedia applications play an important role in a digital library environment, since they allow one to efficiently disseminate knowledge among differently skilled users through an approach, which is more direct than the classic 'static' documents. In this paper, we propose a new authoring approach based on an innovative presentation structure and a new class of content-based constraints. Thanks to a flexible heuristic process, such features allow the author to easily combine several multimedia objects into a multi-topic presentation, whose different contents can be freely chosen by end users according to their preferences or skills
