Injectivity and the Law of Demand
22 Pages Posted: 19 Aug 2019
Date Written: August 15, 2019
Establishing that a demand mapping is injective is core first step for a variety of methodologies. When a version of the law of demand holds, global injectivity can be checked by seeing whether the demand mapping is constant over any line segments. When we add the assumption of differentiability, we obtain necessary and sufficient conditions for injectivity that generalize classical Gale and Nikaido (1956) conditions for quasi-definite Jacobians.
Keywords: Injectivity, Law of Demand, Quasilinear Utility
JEL Classification: C00; D11
Suggested Citation: Suggested Citation