Nonlinear BSDEs with two optional Doob's class barriers satisfying weak Mokobodzki's condition and extended Dynkin games

TL;DR

This paper establishes existence results for nonlinear reflected backward stochastic differential equations with two optional barriers under weak conditions, and applies these results to solve extended nonlinear Dynkin games with saddle points.

Contribution

It introduces a framework for RBSDEs with minimal assumptions on barriers and generator, extending the theory to broader classes of problems.

Findings

Existence of solutions to RBSDEs under weak Mokobodzki's condition.

Representation of Dynkin game value via RBSDE solutions.

Conditions for the existence of saddle points in nonlinear Dynkin games.

Abstract

We study reflected backward stochastic differential equation (RBSDEs) on the probability space equipped with a Brownian motion. The main novelty of the paper lies in fact that we consider the following weak assumptions on the data: barriers are optional of class (D) satisfying weak Mokobodzki's condition, generator is continuous and non-increasing with respect to the value-variable (no restriction on the growth) and Lipschitz continuous with respect to the control-variable, and the terminal condition and the generator at zero are supposed to be merely integrable. We prove that under these conditions on the data there exists a solution to corresponding RBSDE. In the second part of the paper, we apply the theory of RBSDEs to solve basic problems in Dynkin games driven by nonlinear expectation based on the generator mentioned above. We prove that the main component of a solution to RBSDE represents the value process in corresponding extended nonlinear Dynkin game. Moreover, we provide sufficient condition on the barriers guaranteeing the existence of the value for nonlinear Dynkin games and the existence of a saddle point.