Title
Characterizations of coverings for upper approximation operators being closure operators
Abstract
In this paper, we define two conditions of symmetry for the covering C in a covering-based approximation space ( U , C ) . By using these conditions and the triangle chain condition, we give general, topological and intuitive characterizations of the covering C for three types of covering-based upper approximation operators being closure operators. We also give descriptions of ( U , C ) in terms of information exchange systems when these operators are closure operators. These results answer an open problem raised in Ge et al. (2012). As an example application of our characterizations, we discuss the problem of implications among conditions for different types of covering-based upper approximation operators being closure operators.
Year
DOI
Venue
2015
10.1016/j.ins.2015.03.060
Information Sciences: an International Journal
Keywords
Field
DocType
closure operator
Discrete mathematics,Open problem,Closure operator,Operator norm,Operator (computer programming),Upper approximation,Operator theory,Mathematics,Spectral theorem
Journal
Volume
Issue
ISSN
314
C
0020-0255
Citations 
PageRank 
References 
6
0.40
37
Authors
5
Name
Order
Citations
PageRank
Xiaoxia Bian160.40
Pei Wang23116.88
Zuoming Yu3464.22
Xiaole Bai4109457.04
Bin Chen560.40