Ergodicity for stochastic T-monotone parabolic obstacle problems

This work aims to investigate the existence of ergodic invariant measures and its uniqueness, associated with obstacle problems governed by a T T -monotone operator defined on Sobolev spaces and driven by a multiplicative noise in a bounded domain of Rᵈ R d with homogeneous boundary conditions. We show that the solution defines a Markov-Feller semigroup defined on the space of real bounded continuous functions of a convex subset related to the obstacle and we prove the existence of ergodic invariant measures and its uniqueness, under suitable assumptions. Our method relies on a combination of Krylov-Bogoliubov theorem, Krein-Milman theorem and Lewy-Stampacchia inequalities to control the reflection measure.