2025/08/05 by Goodair, Daniel
#Analysis of PDEs (math.AP) #FOS: Mathematics #Probability (math.PR)
paper · doi:10.48550/arxiv.2508.03424
We prove that a solution, in a variational framework, to the Stratonovich stochastic partial differential equation with noise G(t, Ψt) ∘ dWt is given by a solution to the Itô equation with Itô-Stratonovich corrector (1)/(2)∑i=1^∞ DuGi(t, Ψt)[Gi(t,Ψt)]dt. Here Gi denotes the action of G on the ith component of the cylindrical noise, and DuGi 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.