Measures of non-simplifyingness for conditional copulas and vines

Fuente: arXiv
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Main Author: Derumigny, Alexis
Format: Preprint
Published: 2025
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author Derumigny, Alexis
author_facet Derumigny, Alexis
contents In copula modeling, the simplifying assumption has recently been the object of much interest. Although it is very useful to reduce the computational burden, it remains far from obvious whether it is actually satisfied in practice. We propose a theoretical framework which aims at giving a precise meaning to the following question: how non-simplified or close to be simplified is a given conditional copula? For this, we propose a new framework centered at the notion of measure of non-constantness. Then we discuss generalizations of the simplifying assumption to the case where the conditional marginal distributions may not be continuous, and corresponding measures of non-simplifyingness in this case. The simplifying assumption is of particular importance for vine copula models, and we therefore propose a notion of measure of non-simplifyingness of a given copula for a particular vine structure, as well as different scores measuring how non-simplified such a vine decompositions would be for a general vine. Finally, we propose estimators for these measures of non-simplifyingness given an observed dataset. A small simulation study shows the performance of a few estimators of these measures of non-simplifyingness.
format Preprint
id arxiv_https___arxiv_org_abs_2504_07704
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Measures of non-simplifyingness for conditional copulas and vines
Derumigny, Alexis
Statistics Theory
Other Statistics
62H05
In copula modeling, the simplifying assumption has recently been the object of much interest. Although it is very useful to reduce the computational burden, it remains far from obvious whether it is actually satisfied in practice. We propose a theoretical framework which aims at giving a precise meaning to the following question: how non-simplified or close to be simplified is a given conditional copula? For this, we propose a new framework centered at the notion of measure of non-constantness. Then we discuss generalizations of the simplifying assumption to the case where the conditional marginal distributions may not be continuous, and corresponding measures of non-simplifyingness in this case. The simplifying assumption is of particular importance for vine copula models, and we therefore propose a notion of measure of non-simplifyingness of a given copula for a particular vine structure, as well as different scores measuring how non-simplified such a vine decompositions would be for a general vine. Finally, we propose estimators for these measures of non-simplifyingness given an observed dataset. A small simulation study shows the performance of a few estimators of these measures of non-simplifyingness.
title Measures of non-simplifyingness for conditional copulas and vines
topic Statistics Theory
Other Statistics
62H05
url https://arxiv.org/abs/2504.07704