摘要:Nelsen et al. [20] find bounds for bivariate distribution functionswhen there are constraints on the values of its quartiles.Tankov [25] generalizes this work by giving explicit expressionsfor the best upper and lower bounds for a bivariatecopula when its values on a compact subset of [0; 1]2are known. He shows that they are quasi-copulas and notnecessarily copulas. Tankov [25] and Bernard et al. [3] bothgive sufficient conditions for these bounds to be copulas. Inthis note we give weaker sufficient conditions to ensure thatboth bounds are simultaneously copulas. Furthermore, wedevelop a novel application to quantitative risk managementby computing bounds on a bivariate risk measure. This canbe useful in optimal portfolio selection, in reinsurance, in pricingbivariate derivatives or in determining capital requirementswhen only partial information on dependence is available.
关键词:Copulas; Fréchet-Hoeffding bounds; Capital requirements