The Sticky Lévy Process as a solution to a Time Change Equation

Fuente: arXiv
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Hauptverfasser: Ramírez, Miriam, Bravo, Gerónimo Uribe
Format: Preprint
Veröffentlicht: 2022
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author Ramírez, Miriam
Bravo, Gerónimo Uribe
author_facet Ramírez, Miriam
Bravo, Gerónimo Uribe
contents Stochastic Differential Equations (SDEs) were originally devised by Itô to provide a pathwise construction of diffusion processes. A less explored approach to represent them is through Time Change Equations (TCEs) as put forth by Doeblin. TCEs are a generalization of Ordinary Differential Equations driven by random functions. We present a simple example where TCEs have some advantage over SDEs. We represent sticky Lévy processes as the unique solution to a TCE driven by a Lévy process with no negative jumps. The solution is adapted to the time-changed filtration of the Lévy process driving the equation. This is in contrast to the SDE describing sticky Brownian motion, which is known to have no adapted solutions as first proved by Chitashvili. A known consequence of such non-adaptability for SDEs is that certain natural approximations to the solution of the corresponding SDE do not converge in probability, even though they do converge weakly. Instead, we provide strong approximation schemes for the solution of our TCE (by adapting Euler's method for ODEs), whenever the driving Lévy process is strongly approximated.
format Preprint
id arxiv_https___arxiv_org_abs_2301_00063
institution arXiv
publishDate 2022
record_format arxiv
spellingShingle The Sticky Lévy Process as a solution to a Time Change Equation
Ramírez, Miriam
Bravo, Gerónimo Uribe
Probability
Classical Analysis and ODEs
60G51, 60G17, 34F05
Stochastic Differential Equations (SDEs) were originally devised by Itô to provide a pathwise construction of diffusion processes. A less explored approach to represent them is through Time Change Equations (TCEs) as put forth by Doeblin. TCEs are a generalization of Ordinary Differential Equations driven by random functions. We present a simple example where TCEs have some advantage over SDEs. We represent sticky Lévy processes as the unique solution to a TCE driven by a Lévy process with no negative jumps. The solution is adapted to the time-changed filtration of the Lévy process driving the equation. This is in contrast to the SDE describing sticky Brownian motion, which is known to have no adapted solutions as first proved by Chitashvili. A known consequence of such non-adaptability for SDEs is that certain natural approximations to the solution of the corresponding SDE do not converge in probability, even though they do converge weakly. Instead, we provide strong approximation schemes for the solution of our TCE (by adapting Euler's method for ODEs), whenever the driving Lévy process is strongly approximated.
title The Sticky Lévy Process as a solution to a Time Change Equation
topic Probability
Classical Analysis and ODEs
60G51, 60G17, 34F05
url https://arxiv.org/abs/2301.00063