A dependent multiplier bootstrap for the sequential empirical copula process under strong mixing

TL;DR

This paper develops a sequential, data-adaptive dependent multiplier bootstrap method for the empirical copula process in strongly mixing time series, enabling improved inference and change-point detection.

Contribution

It generalizes the dependent multiplier bootstrap to a sequential, automatic framework suitable for strongly mixing data, facilitating advanced copula inference and testing.

Findings

The new bootstrap scheme is valid under weaker mixing conditions.

Simulation results show improved finite-sample performance.

The method enables sequential change-point detection in dependent data.

Abstract

Two key ingredients to carry out inference on the copula of multivariate observations are the empirical copula process and an appropriate resampling scheme for the latter. Among the existing techniques used for i.i.d. observations, the multiplier bootstrap of R\'{e}millard and Scaillet (J. Multivariate Anal. 100 (2009) 377-386) frequently appears to lead to inference procedures with the best finite-sample properties. B\"{u}cher and Ruppert (J. Multivariate Anal. 116 (2013) 208-229) recently proposed an extension of this technique to strictly stationary strongly mixing observations by adapting the dependent multiplier bootstrap of B\"{u}hlmann (The blockwise bootstrap in time series and empirical processes (1993) ETH Z\"{u}rich, Section 3.3) to the empirical copula process. The main contribution of this work is a generalization of the multiplier resampling scheme proposed by B\"{u}cher and Ruppert along two directions. First, the resampling scheme is now genuinely sequential, thereby allowing to transpose to the strongly mixing setting many of the existing multiplier tests on the unknown copula, including nonparametric tests for change-point detection. Second, the resampling scheme is now fully automatic as a data-adaptive procedure is proposed which can be used to estimate the bandwidth parameter. A simulation study is used to investigate the finite-sample performance of the resampling scheme and provides suggestions on how to choose several additional parameters. As by-products of this work, the validity of a sequential version of the dependent multiplier bootstrap for empirical processes of B\"{u}hlmann is obtained under weaker conditions on the strong mixing coefficients and the multipliers, and the weak convergence of the sequential empirical copula process is established under many serial dependence conditions.