Von Neumann raised the intellectual and mathematical level of economics in <answer>several stunning publications</answer>. For his model of an expanding economy, von Neumann proved the existence and uniqueness of an equilibrium using his generalization of the Brouwer fixed-point theorem. Von Neumann's model of an expanding economy considered the matrix pencil  A − λB with nonnegative matrices A and B; von Neumann sought probability vectors p and q and a positive number λ that would solve the complementarity equation
How did von Neumann raise the level of economics?
several stunning publications