The interpretation of the loss of utility as transport costs in address models of differentiation poses a methodological difficulty. Transport costs implicitly amounts to assume that there is a good neither included in the differentiated sector nor in the composite (numeraire) good of the...

In a context where demand for the services of a durable good changes over time, and this change may be uncertain, we show in this paper that social welfare may be higher when the monopolist seller can commit to any future price level he wishes than when he cannot. Moreover, the equilibrium under...