Anisotropic simplicial minisuperspace model

The computation of the simplicial minisuperspace wavefunction in the case of anisotropic universes with a scalar matter field predicts the existence of a large classical Lorentzian universe like our own at late timesComment: 19 pages, Latex, 6 figure

Agreeing to disagree in a countable space of equiprobable states

An example is given in which agents agree to disagree, showing that Aumann's (1976) Agreement Theorem does not extend to a countable space of equiprobable states of nature. Even in this unorthodox setting, if the sets of the information partitions are intervals, an agreement theorem holds. A result that describes the margin for disagreement is also obtained.Agreeing to disagree, Interactive epistemology, Bounded rationality.

Uncertain delivery in markets for lemons

The notion of uncertain delivery is extended to study exchange economies in which agents have different abilities to distinguish between goods (for example a car in good condition versus a car in bad condition). In this setting, it is useful to distinguish goods not only by their physical characteristics,but also by the agent that is bringing them to the market. Equilibrium is shown to exist, and characterized by the fact that agents always receive the cheapest bundle among those that they cannot distinguish from truthful delivery. Several examples are presented as an illustration.General equilibrium, Asymmetric information, Adverse selection, Uncertain delivery, Pool, Delivery rates

Past expectations as a determinant of equilibrium prices - hysteresis in a simple economy

We give an illustration of hysteresis (path-dependence) in a simple economy. In the presence of multiple possible equilibrium prices, we find that past expectations determine present prices. This phenomenon of path-dependence is robust under perturbations of the economy.Hysteresis, Path-dependence, Tatônnement, Equilibrium selection

Free daily newspapers: too many incentives to print?

We consider a model in which a free daily newspaper distributes news to readers and sells ad-space to advertisers, having private information about its readership. Depending on the type of readers in the market, the newspaper's may have a "plentiful and seeking" audience or a "lacking and avoiding" audience. We find that if the readers are plentiful and seeking, the newspaper prints an excessive number of copies. The rationale for this over-printing strategy lies on the newspaper's need to send a credible signal to the advertisers that there are plentiful and seeking readers in the market. When the readers are lacking and avoiding, the newspaper chooses the socially optimal tirage (does not try to cheat the advertisers).two-sided markets, asymmetric information, free press

Agreeing to Disagree with Multiple Priors

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 priors to be updated according to the maximum likelihood criterion, then, under these same assumptions, agents may still agree to disagree. For the Agreement Theorem to hold, it is also necessary to assume that the maximum likelihood priors are commonly known and not disjoint. To show that these hypotheses are necessary, we give several examples in which agents agree to disagree.Agreeing to disagree, multiple priors, Aumann's Agreement Theorem

Costly horizontal differentiation

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 differentiation costs are low, there is maximum differentiation. When they are intermediate, there is partial differentiation, with a degree of differentiation that decreases with the differentiation costs. When they are above a certain threshold, there is no equilibrium. In any case, the socially optimal degree of differentiation is always lower than the equilibrium level. We also study the case of collusion between firms. If firms can combine locations but not prices, they locate asymmetrically when differentiation costs are high and choose maximum differentiation when they are low. When collusion extends to price setting, there is partial differentiation.Costly product differentiation, Spatial competition, Hotelling model

Subjective Expectations Equilibrium in Economies with Uncertain Delivery

In economies with uncertain delivery, agents trade their endowments for lists instead of bundles. A list specifies a set of bundles such that the agent has the right to receive one of them. In this paper, with continuity conditions on private beliefs about the bundle that will be delivered, we establish existence of a subjective expectations equilibrium.Private information, Uncertain delivery, Subjective expectations equilibrium, General equilibrium, Incomplete information, Real options.

Private Information: Similarity as Compatibility

We investigate the continuity of equilibrium in differential information economies with a finite number of agents. In this setting, agents can make contingent contracts based on events that are commonly observed. With private information modelled as finite partitions of a compact and metrizable space of states of nature, we introduce a topology on information that takes into account the compatibility of information fields in assessing similarity between private information fields. This topology allows us to establish upper semicontinuity of the private core correspondence.Differential Information Economy, Asymmetric Information, Radner Equilibrium, Private Core, Topologies on Information.