International audienceArtificial intelligence (AI) traditionally deals with knowledge rather than with data (with the noticeable exception of machine learning). The term "knowledge" refers here to information with a generic flavor, while "data" refers to information pertaining to (collections of) particular cases. The formalization of reasoning patterns with data has been much less studied until now than knowledge representation and its application to knowledge-based systems and reasoning, possibly in presence of imperfect information. Data are positive in nature by manifesting the possibility of what is observed or reported, and contrast with knowledge that delimit the extent of what is potentially possible by specifying what is impossible...