Substituabilités entre demandes de facteurs induites par les demandes de biens

Answers to various questions of applied macroeconomics depend on the valuesgiven to elasticities of substitution between the demands for factors, these demands beingaggregated across productive sectors. Such elasticities reflect not only substitutabilities withinproductive sectors, but also substitutabilities arising from the system of demand functions forgoods, showing how the latter demands react to changes in the relative prices of goods. Afairly general model leads to a relation linking changes in factor relative prices to changes inthe aggregate demands for these factors. The relation is applied to particular specifications,especially for the case of two factors to a CES economy and to an economy with a nonhomotheticsystem of demand functions for goods. Thus, the relation exhibited here lendsitself to studies about how, at the aggregate level, factor substitutabilities depend not only onthe forms of production and goods demand functions, but also on heterogeneity across the setof parameters characterizing these functions.