Kerr-AdS and Kerr-dS solutions revisited

We reconsider the Kerr metric with cosmological term $\Lambda$ imposing the condition that the angular velocity $\omega$ of the dragging of the inertial frames vanishes at spatial boundaries. Some properties of the extreme black holes in the revisited solutions are discussed.Comment: 14 pages, Latex2e, 3 figure

Interior Optima and the Inada Conditions

We present a new proof of the interiority of the policy function based on the Inada conditions. It is based on supporting properties of concave functions.growth model ; Inada conditions ; policy function

Monetary Equilibrium and the Differentiability of the Value Function

In this study we offer a new approach to proving the differentiability of the value function, which complements and extends the literature on dynamic programming. This result is then applied to the analysis of equilibrium in the recent class of monetary economies developed in [13]. For this type of environments we demonstrate that the value function is differentiable and this guarantees that the marginal value of money balances is well defined.value function ; optimal plans ; money

Communication, commitment, and deception in social dilemmas: experimental evidence

Social norms of cooperation are studied under several forms of communication. In an experiment, strangers could make public statements before playing a prisoner’s dilemma. The interaction was repeated indefinitely, which generated multiple equilibria. Communication could be used as a tool to either signal intentions to coordinate on Pareto-superior outcomes, to deceive others, or to credibly commit to actions. Some forms of communication did not promote the incidence of efficient Nash play, and sometimes reduced it. Surprisingly, cooperation suffered when subjects could publicly commit to actions.

The coordination value of monetary exchange: Experimental evidence

Under what conditions can cooperation be sustained in a network of strangers? Here we study the role of institutions and uncover a new behavioral foundation for the use of monetary systems. In an experiment, anonymous subjects could cooperate or defect in bilateral random encounters. This sequence of encounters was indefinite; hence multiple equilibria were possible, including full intertemporal cooperation supported by a social norm based on community punishment of defectors. We report that such social norm did not emerge. Instead, the availability of intrinsically worthless tokens favored the coordination on intertemporal cooperation in ways that networks of strangers were unable to achieve through social norms.

A Theoretical Foundation for Bilateral Matching Mechanisms

This work introduces a rigorous set-theoretic foundation of bilateral matching mechanisms and studies their properties in a systematic manner. By providing a unified framework to study ilateral matching mechanisms, we formalize how different spatial/informational constraints can be implemented via a careful selection of matching mechanisms. In particular, this paper explains why and how various matching mechanisms generate different degrees of information isolation in the economyspatial interactions, matching, information frictions

Brans-Dicke wormhole and space-time foam

We introduce, by means of the Brans-Dicke scalar field, space-time fluctuations at scale comparable to Planck length near the event horizon of a black hole and examine their dramatic effects.Comment: 5 pages, LateX2e, to appear in Proceedings of "MG IX MM", July 2-8 2000, Rome, Ital