On a Parameterized System of Nonlinear Equations with Economic Applications
We study a parameterized system of nonlinear equations. Given a nonempty, compact, and convex set, an affine function, and a point-to-set mapping from the set to the Euclidean space containing the set, we constructively prove that, under certain (boundary) conditions on the mapping, there exists a connected set of zero points of the mapping, i.e., the origin is an element of the image for every point in the connected set, such that the connected set has a nonempty intersection with both the face at which the affine function is minimized and the face at which that function is maximized. This result generalizes and unifies several well-known existence theorems including Browders fixed point theorem and Ky Fans coincidence theorem. An economic application with constrained equilibria is also discussed.
parameterized system of nonlinear equations fixed point variational inequality algorithm equilibrium