Abstract
A big amount of important, “economically relevant” information, is buried into unstructured “narrative” information resources: This is true, for example, for most of the corporate knowledge documents (memos, policy statements, reports, minutes, etc.), for the news stories, the normative and legal texts, the medical records, many intelligence messages as well as for a huge fraction of the information stored on the Web. In these “narrative documents,” or “narratives,” the main part of the information content consists in the description of “events” that relate the real or intended behavior of some “actors” (characters, personages, etc.)—the term “event” is taken here in its more general meaning, also covering strictly related notions like fact, action, state, and situation. These actors try to attain a specific result, experience particular situations, manipulate some (concrete or abstract) materials, send or receive messages, buy, sell, deliver, and so forth. Note that in these narratives, the actors or personages are not necessarily human beings; we can have narrative documents concerning, for example, the vicissitudes in the journey of a nuclear submarine (the “actor,” “subject,” or “personage”) or the various avatars in the life of a commercial product. Note also that even if a large amount of narrative documents concerns natural language (NL) texts, this is not necessarily true. A photo representing a situation that verbalized could be expressed as “Three nice girls are lying on the beach” is not of course an NL text, yet it is still a narrative document.