Existence and Uniqueness of Price Equilibria in Defender

John R. Hauser and Birger Wernerfelt

This not provides a formal proof that for the defender model, with informally distributed tastes, the Nash price equilibrium exist and, for a given set of positions, that they are unique. We also Show that the profit function is well-behaved-continuous and quasi-concave-and that the maximum occurs on the concave of the curve.

(pricing, positioning)