Approximation Space and LEM2-like Algorithms for Computing Local Coverings

Issue title: Concurrency Specification and Programming (CS&P)

Article type: Research Article

Authors: Grzymala-Busse, Jerzy W. | Rz�sa, Wojciech

Affiliations: Department of Electrical Engineering and Computer Science, University of Kansas, Lawrence, KS 66045, USA. [email protected] | Department of Computer Science, University of Rzeszow, 35–310 Rzeszow, Poland. [email protected]

Note: [] Address for correspondence: Department of Electrical Engineering and Computer Science, University of Kansas, Lawrence, KS 66045, USA

Abstract: In this paper we discuss approximation spaces that are useful for studying local lower and upper approximations. Set definability and properties of the approximation space, including best approximations, are considered as well. Finding best approximations is a NP-hard problem. Finally, we present LEM2-like algorithms for determining local lower and upper coverings for a given incomplete data set. Lower and upper approximations, associated with these coverings, are sub-optimal.

Journal: Fundamenta Informaticae, vol. 85, no. 1-4, pp. 205-217, 2008