English

Small ball probabilities and a support theorem for the stochastic heat equation

Probability 2021-02-16 v2

Abstract

We consider the following stochastic partial differential equation on t0,x[0,J],J1t \geq 0, x\in[0,J], J \geq 1 where we consider [0,J][0,J] to be the circle with end points identified: \begin{equation*} \partial_t{\mathbf u}(t,x) =\frac{1}{2}\,\partial_x^2 {\mathbf u}(t,x) + {\mathbf g}(t,x,\mathbf u) + {\mathbf \sigma}(t,x, {\mathbf u})\dot {\mathbf W}(t,x) , \end{equation*} and W˙(t,x)\dot {\mathbf W }(t,x) is 2-parameter dd-dimensional vector valued white noise and σ{\mathbf \sigma} is function from R+×R×RdRd{\mathbb R}_+\times {\mathbb R} \times {\mathbb R}^d \rightarrow {\mathbb R}^d to space of symmetric d×dd\times d matrices which is Lipschitz in u\mathbf u. We assume that σ\sigma is uniformly elliptic and that g\mathbf g is uniformly bounded. Assuming that u(0,x)0{\mathbf u}(0,x) \equiv \mathbf 0, we prove small-ball probabilities for the solution u\mathbf u. We also prove a support theorem for solutions, when u(0,x){\mathbf u}(0,x) is not necessarily zero.

Keywords

Cite

@article{arxiv.2006.07978,
  title  = {Small ball probabilities and a support theorem for the stochastic heat equation},
  author = {Siva Athreya and Mathew Joseph and Carl Mueller},
  journal= {arXiv preprint arXiv:2006.07978},
  year   = {2021}
}
R2 v1 2026-06-23T16:18:57.298Z