Approximate reasoning an evidence theory

Abstract One approach to approximate reasoning is to make use of results arising from research in evidence theory. In this theory, evidence is represented by evidential functions , and the reasoning is conducted by evidential operations on them. Our objective in this paper is to contribute to the understanding of these evidential operations. We discuss some basic operations on evidential functions: the orthogonal sum operation, the discount operation, the refining operation, and the coarsening operation. For example, we show that coarsening and discount operations are not commutative with the orthogonal sum operation. The relationships among the orthogonal sum, refining, coarsening, and discount operations are all investigated. A well-known case study from the evidential reasoning literature is used to illustrate the interplay between these operations.