We consider reflected backward stochastic different equations with optional barrier and so-called regulated trajectories, i.e trajectories with left and right finite limits. We prove existence and uniqueness results. We also show that the solution may be approximated by a modified penalization method. Application to an optimal stopping problem is given.
MSC 2000 subject classifications: primary 60H10; secondary 60G40.Keywords: Reflected backward stochastic differential equation, processes with regulated trajectories, modified penalization method, optimal stopping problem.M loc (resp. M) is the set of all F-martingales (resp. local martingales) M such that M 0 = 0. M p , p ≥ 1, denotes the space of all M ∈ M such that