30 Years of Rough Sets and Future Perspectives

摘要

In the development of rough set theory and applications, one can distinguish three main stages. While the first period was based on the assumption that objects are perceived by means of partial information represented by attributes, in the second period it was assumed that information about the approximated concepts is partial too. Approximation spaces and searching strategies for relevant approximation spaces were recognized as the basic tools for rough sets. Important achievements both in theory and applications were obtained. Nowadays, a new period for rough sets is emerging.