Comparison results for positive supermodular dependent Markov tree distributions

Fuente: arXiv
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Auteurs principaux: Ansari, Jonathan, Ritter, Moritz
Format: Preprint
Publié: 2024
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author Ansari, Jonathan
Ritter, Moritz
author_facet Ansari, Jonathan
Ritter, Moritz
contents Positive dependencies have been compared in the literature under rather strong assumptions such as equality of conditional distributions, exchangeability, or stationarity. We establish supermodular ordering results for distributions that are Markov with respect to a tree structure. Our comparison results rely on simple stochastic monotonicity conditions and a pointwise ordering of bivariate copulas associated with the edges of the underlying tree. We also study flexibility of the marginal distributions in stochastic and convex order. As a consequence, we obtain first- and second-order stochastic dominance esults for extreme order statistics and sums of positively dependent random variables. As an application, we investigate distributional robustness of the maximum of a perturbed random walk under model uncertainty. Several examples and a detailed discussion of the assumptions demonstrate the generality of our results and reveal deeper insights into non-intuitive positive dependence properties of multidimensional distributions.
format Preprint
id arxiv_https___arxiv_org_abs_2404_17441
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Comparison results for positive supermodular dependent Markov tree distributions
Ansari, Jonathan
Ritter, Moritz
Statistics Theory
Probability
Primary 60E15, 62H05, secondary 60G50, 62M05, 62P05
Positive dependencies have been compared in the literature under rather strong assumptions such as equality of conditional distributions, exchangeability, or stationarity. We establish supermodular ordering results for distributions that are Markov with respect to a tree structure. Our comparison results rely on simple stochastic monotonicity conditions and a pointwise ordering of bivariate copulas associated with the edges of the underlying tree. We also study flexibility of the marginal distributions in stochastic and convex order. As a consequence, we obtain first- and second-order stochastic dominance esults for extreme order statistics and sums of positively dependent random variables. As an application, we investigate distributional robustness of the maximum of a perturbed random walk under model uncertainty. Several examples and a detailed discussion of the assumptions demonstrate the generality of our results and reveal deeper insights into non-intuitive positive dependence properties of multidimensional distributions.
title Comparison results for positive supermodular dependent Markov tree distributions
topic Statistics Theory
Probability
Primary 60E15, 62H05, secondary 60G50, 62M05, 62P05
url https://arxiv.org/abs/2404.17441