Calendar units, such as months and days, clock units, such as hours and seconds, and specialized units, such as business days and academic years, play a major role in a wide range of information system applications. System support for reasoning about these units, called granularities in this book,...

Mr Administrator,Dear colleagues,Ladies and Gentlemen, It is a great honour for me to inaugurate the first Chair devoted to informatics at the Collège de France, after introducing this science within the Liliane Bettencourt Annual Chair of Technological Innovation in 2007/2008 and inaugurating the Annual Chair of Information Technology and Digital Sciences in 2009/2010. I would like to thank all those who contributed to the creation of this Chair, which is of prime importance for the entire Fr...