On the existence of a trivariate copula with given values of a trivariate quasi-copula at several points

Autor: Manuel íbeda-Flores, Juan Fernández Sánchez, Bernard De Baets, Hans De Meyer
Rok vydání: 2013
Předmět:
Zdroj: Fuzzy Sets and Systems. 228:3-14
ISSN: 0165-0114
DOI: 10.1016/j.fss.2012.07.006
Popis: The existence of a (multivariate) copula with a given value of a (multivariate) quasi-copula at a single point is known. In the bivariate case, the existence of a copula with given values of a quasi-copula at two or three arbitrary points is also known. In this paper, we give an alternative proof of the existence of a trivariate copula with a given value of a trivariate quasi-copula at a single point. This proof relies on the reformulation of the existence problem as a linear programming minimization problem and its solution by means of the simplex algorithm. The same method is then used to prove the existence of a trivariate copula with given values of a trivariate quasi-copula at two arbitrary points in the unit cube. We furthermore establish a counter-example showing that the existence for given values at three points is not guaranteed. This completes the analysis of the trivariate case.
Databáze: OpenAIRE