  The Dempster-Shafer theory of evidence has been used intensively to deal with
uncertainty in knowledge-based systems. However the representation of uncertain
relationships between evidence and hypothesis groups (heuristic knowledge) is
still a major research problem. This paper presents an approach to representing
such heuristic knowledge by evidential mappings which are defined on the basis
of mass functions. The relationships between evidential mappings and multi
valued mappings, as well as between evidential mappings and Bayesian multi-
valued causal link models in Bayesian theory are discussed. Following this the
detailed procedures for constructing evidential mappings for any set of
heuristic rules are introduced. Several situations of belief propagation are
discussed.
