Depending on ethical beliefs, different decisions emerge for resolving the carbon dioxide (CO/sup 2/) issue. It is doubtful that an international consensus can be reached on a correct ethical criterion. Perhaps the best strategy would be to delay acceptance of either a particular set of beliefs or the existing scientific evidence and wait for more-accurate and conclusive research to emerge. If the scientific evidence is accepted as valid, and all future generations that will exist are evaluated equally, then the optimal current regulatory strategy is to restrict, as much as possible, current emissions of CO/sup 2/. 17 references, 2 figure, 1 table.

The article examines equilibrium in a competitive market in which the mythical auctioneer is absent and information is costly to gather. As a result, individuals may not be perfectly informed about prices or qualities of what is being sold. According to the author, equilibrium in such markets may differ markedly from the one conventionally studied by neoclassical theory. In particular, the only market equilibrium may be characterized by price dispersion for a homogeneous commodity, the law of the single price does not obtain. The article illustrates this with a model in which all individuals are identical and in which there is no exogenous source of noise, no external disturbances to the market, which have to be equilibrated. In the model, although all individuals have identical preferences and incomes and all firms have identical technologies, some firm charge high prices and others charge low prices. High-price stores earn a larger profit per sale, but make fewer sales. Equilibrium entails equal profits for two kinds of stores, that is, the lower volume of high-price stores exactly compensates for the higher profit per sale. The model that is developed by authors is of interest not only for the insight that it provides into the nature of price dispersion in the economy, but also because it provides at least a partial explanation of some aspects of retailing which otherwise would be difficult to explain.

Noting that a suggested measure of natural resource scarcity, resource rent, is unobservable, we show that rent is linked to (observable) marginal exploration cost. A two-period model of extraction and exploration reveals that rent is equal to this cost when discovery is certain. Under risky exploration, cost data can be used to bound rent. The model also indicates how exploration uncertainty affects the competitive firm's extraction and exploration decisions. Finally, the behavior of U.S. oil and gas exploration costs suggests that these costs were rising in the postwar era, which has different implications for scarcity than indicated by other measures of scarcity.

It is found that the welfare gain per unit of revenue raised is maximized for an export tariff on technology transfer, followed by an import tariff on goods, with an export tariff on goods the poorest policy alternative. These results are derived within a monopolistic competition model, where the production of any good requires some initial research and development (R&D), and technology transfer occurs when R&D is done in one country for production of goods in the other. An intuitive explanation is presented, based on the public-good nature of R&D and also the elasticity of demand for technologies from firms.