Itô-Stratonovich Conversion in Infinite Dimensions for Unbounded, Time-Dependent, Nonlinear Operators

Fuente: arXiv
Saved in:
Bibliographic Details
Main Author: Goodair, Daniel
Format: Preprint
Published: 2025
Subjects:
Online Access:
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1866912521376497664
author Goodair, Daniel
author_facet Goodair, Daniel
contents We prove that a solution, in a variational framework, to the Stratonovich stochastic partial differential equation with noise $G\left(t, Ψ_t\right) \circ dW_t$ is given by a solution to the Itô equation with Itô-Stratonovich corrector $\frac{1}{2}\sum_{i=1}^\infty D_uG_i\left(t, Ψ_t\right)\left[G_i(t,Ψ_t)\right]dt$. Here $G_i$ denotes the action of $G$ on the $i^{th}$ component of the cylindrical noise, and $D_uG_i$ its Fréchet partial derivative in the Hilbert space for which the Itô form is satisfied. The noise operator $G$ may be time-dependent, nonlinear, and unbounded in the sense of differential operators; in the latter case, one must pass to a larger space in order to solve the Stratonovich equation. Our proof relies on martingale techniques, and the results apply to fluid equations with time-dependent and nonlinear transport noise.
format Preprint
id arxiv_https___arxiv_org_abs_2508_03424
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Itô-Stratonovich Conversion in Infinite Dimensions for Unbounded, Time-Dependent, Nonlinear Operators
Goodair, Daniel
Probability
Analysis of PDEs
We prove that a solution, in a variational framework, to the Stratonovich stochastic partial differential equation with noise $G\left(t, Ψ_t\right) \circ dW_t$ is given by a solution to the Itô equation with Itô-Stratonovich corrector $\frac{1}{2}\sum_{i=1}^\infty D_uG_i\left(t, Ψ_t\right)\left[G_i(t,Ψ_t)\right]dt$. Here $G_i$ denotes the action of $G$ on the $i^{th}$ component of the cylindrical noise, and $D_uG_i$ its Fréchet partial derivative in the Hilbert space for which the Itô form is satisfied. The noise operator $G$ may be time-dependent, nonlinear, and unbounded in the sense of differential operators; in the latter case, one must pass to a larger space in order to solve the Stratonovich equation. Our proof relies on martingale techniques, and the results apply to fluid equations with time-dependent and nonlinear transport noise.
title Itô-Stratonovich Conversion in Infinite Dimensions for Unbounded, Time-Dependent, Nonlinear Operators
topic Probability
Analysis of PDEs
url https://arxiv.org/abs/2508.03424