The complementary process of fuzzy medical diagnosis and its properties (Q1083388)

Let S be a set of symptoms, D be a set of diagnoses (causes), P be a set of patients. Let Q, T be fuzzy relations on \(P\times S\), \(P\times D\), respectively. According to \textit{E. Sanchez}'s fuzzy diagnosis, see Fuzzy Sets Syst. 2, 75-86 (1979; Zbl 0399.03040), we have to construct a fuzzy relation R on \(S\times D\), which expresses the causality between symptoms and diagnoses by a suitable combination of Q and T. The author starts from negated symptoms S' and negated diagnoses D' and develops the fuzzy diagnosis for this case according to Sanchez's procedure. Properties of this so-called complementary diagnosis are studied.