@ARTICLE { Rsds3591,
author = {Yao, Yiyu}, 
title = {Relational interpretations of neighborhood operators and rough set approximation operators}, 
journal = {Information Sciences: An International Journal}, 
number = 	{(no. 1-4)}, 
volume = 111, 
pages = {239-259}, 
publisher = {Elsevier Science Inc.}, 
address = {Amsterdam, The Netherlands}, 
month = {November}, 
year = 1998, 
issn = {0020-0255}, 
abstract = {This paper presents a framework for the formulation, interpretation, and comparison of neighborhood systems and rough set approximations using the more familiar notion of binary relations. A special class of neighborhood systems, called 1-neighborhood systems, is introduced. Three extensions of Pawlak approximation operators are analyzed. Properties of neighborhood and approximation operators are studied, and their connections are examined.}, 
keywords = {approximation operators, binary relations, neighborhood systems, rough sets, partitions, coverings, }, 
}