Samanta P.,Katwa College Katwa |
Chakraborty M.K.,Indian Statistical Institute |
Chakraborty M.K.,Jadavpur University
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2011
This paper consists of an extensive survey of various generalized approaches to the lower and upper approximations of a set, the two approximations being first defined by Pawlak while introducing rough set theory. Particularly, relational, covering based and operator based approaches are considered. Categorization of various approaches in terms of implication lattices is shown. Significance of this categorization in rough logics is briefly mentioned. © 2011 Springer-Verlag Berlin Heidelberg.