On the definitions of Giffen and inferior goods

Abstract

We consider Giffen goods for the very general setting of an upper semi-continuous utility function. Two not equivalent definitions for this notions are discussed. Concerning this we show that there exists a (well-defined) nondecreasing demand function R++ → R that is nowhere strictly increasing. Also we reconsider the relation between Giffen and inferior goods. © Springer-Verlag Berlin Heidelberg 2012.