Symmetric difference operators for fuzzy sets (Q1115442)

(T,S,n) is called a De Morgan triplet if T is a t-norm, S a t-conorm, n a strong negation in the unit interval and \(T=n\circ S\circ (n\times n)\). The authors of the paper under review extend the four representations of the symmetric difference operator in the lattice \(({\mathcal P}(X),\min,\max,1-j)\) and obtain four different operators. Furthermore, comparing and analyzing these four operators, the authors describe their properties and discuss the cases in which they are equivalent.