Issue No.02 - March/April (2000 vol.12)
DOI Bookmark: http://doi.ieeecomputersociety.org/10.1109/69.842271
<p><b>Abstract</b>—This paper proposes new definitions of lower and upper approximations, which are basic concepts of the rough set theory. These definitions follow naturally from the concept of ambiguity introduced in this paper. The new definitions are compared to the classical definitions and are shown to be more general, in the sense that they are the only ones which can be used for any type of indiscernibility or similarity relation.</p>
Rough sets, lower and upper approximations, ambiguity, similarity relation.
Roman Slowinski, "A Generalized Definition of Rough Approximations Based on Similarity", IEEE Transactions on Knowledge & Data Engineering, vol.12, no. 2, pp. 331-336, March/April 2000, doi:10.1109/69.842271