@INPROCEEDINGS { Rsds3771,
author = {Bonikowski, Zbigniew}, 
title = {Algebraic Structures of Rough Sets in Representative Approximation Spaces}, 
booktitle = {Proceedings of The International Workshop on Rough Sets in Knowledge Discovery and Soft Computing}, 
conference = {International Workshop on Rough Sets in Knowledge Discovery and Soft Computing}, 
pages = {52--63}, 
year = 2003, 
editor = {Skowron, Andrzej and Szczuka, Marcin}, 
abstract = {In this paper a generalized notion an approximation space is considered. By an approximation space we mean ordered pair (U,C), where U is finite nonempty set and C is a covering of U. According to connections between rough sets and concepts we define two types of approximation operations. Hence we obtain two families of rough sets. We show that these families form lattices in special types of representative approximation spaces. The operations on rough sets defined in the above lattices are analogous to classical operations on sets.}, 
keywords = {rough sets, approximation operations, representative approximation space, algebra of rough sets, }, 
}