Does a Unique Solution Exist for a Nonlinear Rational Expectation Equation with Zero Lower Bound?

摘要

To formalize a nonlinear rational expectation model in macroeconomics as a functional equation, we investigate the existence of a unique solution. Assuming that the probability of large exogenous disturbance occurring is sufficiently small, we prove that a unique solution exists. This result provides a rigorous foundation for research on nonlinear rational expectation models as a natural extension of existing linear models.