We study the effect of quadratic differentiation costs in the Hotelling model of endogenous product differentiation. The equilibrium location choices are found to depend on the magnitude of the differentiation costs (relatively to the transportation costs supported by consumers). When the...

We present an extension of Aumann's Agreement Theorem to the case of multiple priors. If agents update all their priors, then, for the Agreement Theorem to hold, it is sufficient to assume that they have closed, connected and intersecting sets of priors. On the other hand, if agents select the...

We extend an analytically solvable core-periphery model by introducing a monopolistically competitive sector of non-tradable goods. We study how trade costs affect the spatial distribution of economic activity. Trade costs have no effect when the elasticity of substitution among non-tradable...

We consider a version of the intertemporal general equilibrium model of Cox et al. (1985a) with a single production process and two correlated state variables. It is assumed that only one of them, Y2, has shocks correlated with those of the economy's output rate and, simultaneously, that the...

We derive a closed-form solution for the price of a European call option in the presence of ambiguity about the stochastic process that determines the variance of the underlying asset's return. The option pricing formula of Heston (1993) is a particular case of ours, corresponding to the case in...

Literature on dynamic portfolio choice has been finding that volatility risk has low impact on portfolio choice. For example, using long-run U.S. data, Chacko and Viceira (2005) found that intertemporal hedging demand (required by investors for protection against adverse changes in volatility)...

We study sustainability of collusion with optimal penal codes, in markets where demand growth may trigger the entry of a new firm. In contrast with grim trigger strategies, optimal penal codes make collusion easier to sustain before entry than after. We compare different reactions of the...