On the asymptotics of extremal lp-blocks cluster inference

Fuente: arXiv
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Main Authors: Buriticá, Gloria, Wintenberger, Olivier
Format: Preprint
Published: 2022
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author Buriticá, Gloria
Wintenberger, Olivier
author_facet Buriticá, Gloria
Wintenberger, Olivier
contents Extremes occur in stationary regularly varying time series as short periods with several large observations, known as extremal blocks. We study cluster statistics summarizing the behavior of functions acting on these extremal blocks. Examples of cluster statistics are the extremal index, cluster size probabilities, and other cluster indices. The purpose of our work is twofold. First, we state the asymptotic normality of block estimators for cluster inference based on consecutive observations with large lp-norms, for p < 0. The case p=$α$, where $α$ > 0 is the tail index of the time series, has specific nice properties thus we analyze the asymptotic of blocks estimators when approximating $α$ using the Hill estimator. Second, we verify the conditions we require on classical models such as linear models and solutions of stochastic recurrence equations. Regarding linear models, we prove that the asymptotic variance of classical index cluster-based estimators is null as first conjectured in Hsing T. [26]. We illustrate our findings on simulations.
format Preprint
id arxiv_https___arxiv_org_abs_2212_13521
institution arXiv
publishDate 2022
record_format arxiv
spellingShingle On the asymptotics of extremal lp-blocks cluster inference
Buriticá, Gloria
Wintenberger, Olivier
Probability
Statistics Theory
Extremes occur in stationary regularly varying time series as short periods with several large observations, known as extremal blocks. We study cluster statistics summarizing the behavior of functions acting on these extremal blocks. Examples of cluster statistics are the extremal index, cluster size probabilities, and other cluster indices. The purpose of our work is twofold. First, we state the asymptotic normality of block estimators for cluster inference based on consecutive observations with large lp-norms, for p < 0. The case p=$α$, where $α$ > 0 is the tail index of the time series, has specific nice properties thus we analyze the asymptotic of blocks estimators when approximating $α$ using the Hill estimator. Second, we verify the conditions we require on classical models such as linear models and solutions of stochastic recurrence equations. Regarding linear models, we prove that the asymptotic variance of classical index cluster-based estimators is null as first conjectured in Hsing T. [26]. We illustrate our findings on simulations.
title On the asymptotics of extremal lp-blocks cluster inference
topic Probability
Statistics Theory
url https://arxiv.org/abs/2212.13521