Path-by-path regularisation through multiplicative noise in rough, Young, and ordinary differential equations

Fuente: arXiv
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Main Authors: Dareiotis, Konstantinos, Gerencsér, Máté
Format: Preprint
Published: 2022
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author Dareiotis, Konstantinos
Gerencsér, Máté
author_facet Dareiotis, Konstantinos
Gerencsér, Máté
contents Differential equations perturbed by multiplicative fractional Brownian motions are considered. Depending on the value of the Hurst parameter $H$, the resulting equation is pathwise viewed as an ODE, YDE, or RDE. In all three regimes we show regularisation by noise phenomena by proving the strongest kind of well-posedness with irregular drift: strong existence and path-by-path uniqueness. In the Young and smooth regime $H>1/2$ the condition on the drift coefficient is optimal in the sense that it agrees with the one known for the additive case [CG16, Ger22]. In the rough regime $H\in(1/3,1/2)$ we assume positive but arbitrarily small drift regularity for strong well-posedness, while for distributional drift we obtain weak existence.
format Preprint
id arxiv_https___arxiv_org_abs_2207_03476
institution arXiv
publishDate 2022
record_format arxiv
spellingShingle Path-by-path regularisation through multiplicative noise in rough, Young, and ordinary differential equations
Dareiotis, Konstantinos
Gerencsér, Máté
Probability
60H50, 60H10, 60L20
Differential equations perturbed by multiplicative fractional Brownian motions are considered. Depending on the value of the Hurst parameter $H$, the resulting equation is pathwise viewed as an ODE, YDE, or RDE. In all three regimes we show regularisation by noise phenomena by proving the strongest kind of well-posedness with irregular drift: strong existence and path-by-path uniqueness. In the Young and smooth regime $H>1/2$ the condition on the drift coefficient is optimal in the sense that it agrees with the one known for the additive case [CG16, Ger22]. In the rough regime $H\in(1/3,1/2)$ we assume positive but arbitrarily small drift regularity for strong well-posedness, while for distributional drift we obtain weak existence.
title Path-by-path regularisation through multiplicative noise in rough, Young, and ordinary differential equations
topic Probability
60H50, 60H10, 60L20
url https://arxiv.org/abs/2207.03476