Fuzzy implications: alpha migrativity and generalised laws of importation

In this work, we discuss the law of α-migrativity as applied to fuzzy implication functions in a meaningful way. A generalisation of this law leads us to Pexider-type functional equations connected with the law of importation, viz., the generalised law of importation I(C(x,α),y)=I(x,J(α,y)) (GLI) and the generalised cross-law of importation I(C(x,α),y)=J(x,I(α,y)) (CLI), where C is a generalised conjunction. In this article we investigate only (GLI). We begin by showing that the satisfaction of law of importation by the pairs (C, I) and/or (C, J) does not necessarily lead to the satisfaction of (GLI). Hence, we study the conditions under which these three laws are related

Supermigrativity of aggregation functions

A functional inequality, called supermigrativity, was recently introduced for bivariate semi-copulas and applied in various problems arising in the study of aging properties of stochastic systems. Here, we revisit this notion and extend it to the case of aggregation functions in higher dimensions. In particular, we show how supermigrativity can be expressed via monotonicity of a function with respect to logarithmic majorization ordering of real vectors. Various alternative characterizations of supermigrativity are illustrated, together with some of its weaker versions. Several examples show similarities and differences between the bivariate and the general case