Temporal Dynamics in Information Tables

An information table can change over time in several different ways: objects enter/exit the system, new attributes are considered, etc. As a consequence rough set instruments also change. At first, we recall a classification of dynamic increase of information with respect to three different factors: objects, attributes, values. Then, the corresponding changes in rough sets are discussed. Results about approximations, positive region and generalized decision are given and algorithms to update reducts and rules provided.