Relations between copula-based dependence and ageing. A new approach based on partial orderings for copulas

In the case where dependence concept is based on notions of dependence orderings for copulas, we propose a new approach to investigate the inter-relations among dependence, univariate and bivariate ageing concepts for exchangeable random variables. Such an approach allows to extend some previously known inter-relations to weak dependence concepts and to propose two indeces of univariate a bivariate ageing.