| This dissertation considers the question of solving economic equilibrium problems---formulated as complementarity problems and, more generally, mathematical programs with equilibrium constraints (MPECs)---as nonlinear programs, using an interior-point approach. These problems pose theoretical difficulties for nonlinear solvers, including interior-point methods. We examine ways to resolve these issues, both theoretically and in practice, and then apply the newly developed tools to some varied and interesting applications, such as game theory, auctions and finance. |
