Fast convergence rates for estimating the stationary density in SDEs driven by a fractional Brownian motion with semi-contractive drift

Fuente: arXiv
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Autores principales: Amorino, Chiara, Nualart, Eulalia, Panloup, Fabien, Sieber, Julian
Formato: Preprint
Publicado: 2024
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author Amorino, Chiara
Nualart, Eulalia
Panloup, Fabien
Sieber, Julian
author_facet Amorino, Chiara
Nualart, Eulalia
Panloup, Fabien
Sieber, Julian
contents We study the estimation of the invariant density of additive fractional stochastic differential equations with Hurst parameter $H \in (0,1)$. We first focus on continuous observations and develop a kernel-based estimator achieving faster convergence rates than previously available. This result stems from a martingale decomposition combined with new bounds on the (conditional) convergence in total variation to equilibrium of fractional SDEs. For $H<1/2$, we further refine the rates based on recent bounds on the marginal density. We then extend the methodology to discrete observations, showing that the same convergence rates can be attained. Moreover, we establish concentration inequalities for the estimator and introduce a data-driven bandwidth selection procedure that adapts to unknown smoothness. Numerical experiments for the fractional Ornstein-Uhlenbeck process illustrate the estimator's practical performance. Finally, our results weaken the usual convexity assumptions on the drift component, allowing us to consider settings where strong convexity only holds outside a compact set.
format Preprint
id arxiv_https___arxiv_org_abs_2408_15904
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Fast convergence rates for estimating the stationary density in SDEs driven by a fractional Brownian motion with semi-contractive drift
Amorino, Chiara
Nualart, Eulalia
Panloup, Fabien
Sieber, Julian
Statistics Theory
Probability
We study the estimation of the invariant density of additive fractional stochastic differential equations with Hurst parameter $H \in (0,1)$. We first focus on continuous observations and develop a kernel-based estimator achieving faster convergence rates than previously available. This result stems from a martingale decomposition combined with new bounds on the (conditional) convergence in total variation to equilibrium of fractional SDEs. For $H<1/2$, we further refine the rates based on recent bounds on the marginal density. We then extend the methodology to discrete observations, showing that the same convergence rates can be attained. Moreover, we establish concentration inequalities for the estimator and introduce a data-driven bandwidth selection procedure that adapts to unknown smoothness. Numerical experiments for the fractional Ornstein-Uhlenbeck process illustrate the estimator's practical performance. Finally, our results weaken the usual convexity assumptions on the drift component, allowing us to consider settings where strong convexity only holds outside a compact set.
title Fast convergence rates for estimating the stationary density in SDEs driven by a fractional Brownian motion with semi-contractive drift
topic Statistics Theory
Probability
url https://arxiv.org/abs/2408.15904