Redundancy; Fuzzy rules; Linguistic description; Perception-based logical deduction

In this paper we will investigate which fuzzy/linguistic rules are redundant in systems of such rules called linguistic descriptions. We present a formal definition of redundancy and show that rules which are seemingly redundant can be in fact indispensable. These results apply for IF-THEN rules which use evaluative linguistic expressions (e.g., small, very big, etc.) and inference method called perception-based logical deduction (PbLD). However, they are also valid for inference systems which use compatible design choices with PbLD.