Be Brief, Be to the Point, ... Be Seated or Relevant Responses in Man/Machine Conversation

In the dialogue part of our system, we have t r ied to increase the user's possib i l i t ies to c r i t i cize the machine's results flfd require explanations of them. The system must then provide a clear j u s t i f icat ion : either by furnishing the chain of reasoning or by asking a "good question" when it fa i led . The system must also be able to engage in a real dialogue, with more than one question / one answer. To do that, the system must build and use several kinds of representation : the reasoning, the topics and a mode] of the user, which is used to ta i lo r the system's responses.