Special Session 168: Stochastic Analysis and Large Scale Interacting Systems

Sharp upper bounds on hitting probabilities for the solution to the stochastic heat equation on the line
Robert Dalang
Ecole Polytechnique Federale de Lausanne (EPFL)
Switzerland
Co-Author(s):    Fei Pu (Beijing) & David Nualart (Kansas)
Abstract:
For Gaussian random fields with values in $\R^d$, sharp upper and lower bounds on the probability of hitting a fixed set have been available for many years. These apply in particular to the solutions of systems of linear SPDEs. For non-Gaussian random fields, the available bounds are less sharp. For systems of stochastic heat equations, a sharp lower bound was obtained in [R.C. Dalang and F. Pu, Optimal lower bounds on hitting probabilities for stochastic heat equations in spatial dimension k \geq 1. Electron. J. Probab. 25 (2020), Paper No. 40, 31 pp]. Here, we obtain the corresponding sharp upper bound.