A necessary and sufficient condition for an input to be inferior is that, taking into account the input adjustment, an increase of its price raises the marginal productivity of all inputs. Contrary to a widespread opinion, it is not necessary that (some) inputs are “rivals” (i.e., that some...

We examine the role of per capita income in closed and open economy models of monopolistic competition based on non-homothetic directly additive preferences à la Dixit-Stiglitz, as in Krugman (1979). In a closed economy with free entry income is always neutral on markups and firm size. In a...

We examine the role of per capita income in closed and open economy models of monopolistic competition based on non-homothetic directly additive preferences a la Dixit-Stiglitz, as in Krugman (1979). In a closed economy with free entry income is always neutral on markups and firm size. In a...

We study monopolistic competition with preferences over differentiated goods characterized by a separable indirect utility rather than a separable direct utility as in the Dixit-Stiglitz model, with the CES case as the only common ground. Examples include linear and log-linear direct demands. In...

We study monopolistic competition under indirect additivity of preferences. This is dual to the Dixit-Stiglitz model, where direct additivity is assumed, with the CES case as the only common ground. Other examples include (perceived) demand functions that are exponential or linear. Our...

The Allen/Uzawa elasticity of substitution, still commonly used in the empirical studies to account for "net" substitutability, has been subject to a number of theoretical criticisms. In this paper we reconsider the Allen/Uzawa elasticity of substitution as a measure of "gross" substitutability,...