Cuong Le Van

Overlapping Sets of Priors and the Existence of Efficient Allocations and Equilibria for Risk Measures

The overlapping expectations and the collective absence of arbitrage conditions introduced in the economic literature to insure existence of Pareto optima and equilibria with short-selling when investors have a single belief about future returns, is reconsidered. Investors use measures of risk. The overlapping sets of priors and the Pareto equilibrium conditions introduced by Heath and Ku for coherent risk measures are respectively reinterpreted as a weak no-arbitrage and a weak collective absence of arbitrage conditions and shown to imply existence of Pareto optima and Arrow-Debreu equilibria.

Transitional dynamics in an R&D-based growth model with natural resources

In this paper, we prove the existence and uniqueness of the optimal path for a resource endowed economy with R&D. This path converges to an optimal steady state, which is a saddle point, for each type of resources (renewable or non-renewable). In this steady state, a finite size resource sector coexists with other continuously growing sectors. In comparison, the corresponding decentralized equilibrium is suboptimal and there is either over- or under-investment in R&D from the social planner’s perspective. At optimum, positive long-run growth will be sustained regardless type of resources used.

Arbitrage and asset market equilibrium in infinite dimensional economies with short-selling and risk-averse expected utilities

We consider a model with an infinite number of states of nature, von Neumann–Morgenstern utilities, where agents have different probability beliefs and where short sells are allowed. We show that no-arbitrage conditions, defined for finite dimensional asset markets models, are not sufficient to ensure existence of equilibrium in presence of an infinite number of states of nature. However, if the individually rational utility set U is compact, we obtain an equilibrium. We give conditions which imply the compactness of U. We give examples of non-existence of equilibrium when these conditions do not hold.

Interest rates parity and no arbitrage as equivalent equilibrium conditions in the international financial assets and goods markets

In this paper, we consider a two-period consumption model with many financial assets. In the spirit of Hart, consumers purchase financial assets in period 0 and consume in period 1. We differ from Hart by considering that each agent is a country. We provide conditions for the existence of an equilibrium in both international financial assets and goods markets. First, we introduce a weaker notion of Uncovered Interest (rate) Parity (UIP) called Weak Uncovered Interest (rate) Parity (WUIP), and we show its equivalence to the no-arbitrage condition in the international financial markets. Second, we introduce the concept of common no arbitrage and we show its equivalence to UIP. These results bridge concepts of no arbitrage in general equilibrium theory and financial microeconomics and of interest parity in international financial macroeconomics. In a multi-country model with many currencies and only one good, we introduce a country-specific conversion rate which transforms the returns on assets valued in local currency into units of physical good. We the define also the exchange rates between currencies of different countries. The UIP condition is required for the existence of an equilibrium in both international financial assets and goods markets and for the existence of the Law of One Price.