05616692

a

05616692 Grzymala-Busse, Jerzy W. Rzasa, Wojciech Local approximations. Corchado, Emilio (ed.) et al., Intelligent data engineering and automated learning -- IDEAL 2009. 10th international conference, Burgos, Spain, September 23--26, 2009. Proceedings. Berlin: Springer (ISBN 978-3-642-04393-2/pbk). Lecture Notes in Computer Science 5788, 9-16 (2009). 2009 Berlin: Springer EN

doi:10.1007/978-3-642-04394-9_2

Summary: In this paper we analyze the basic concepts of rough set theory, lower and upper approximations, defined in an approximation space $(U,\bold{L})$, where $U$ is a nonempty and finite set and L is a fixed family of subsets of $U$. Some definitions of such lower and upper approximations are well known, some are presented in this paper for the first time. Our new definitions better accommodate applications to mining incomplete data, i.e., data with missing attribute values. An illustrative example is also presented in this paper.