In the model of monopolistic competition on the circle, a product is identified by a single locational characteristic representing its brand or variety. The ability of a variety to compete with other varieties a given distance away (its specialization as quantified by transportation losses) is exogenously given in the standard model. Here, specialization is a choice variable selected by the firm. An equilibrium is derived, where the degree of specialization is endogenously determined. The effect of endogenizing specialization makes the Hotelling-Lancaster-Chamberlin model of monopolistic competition isomorphic to the Dixit-Stiglitz-Ethier formulation, without sacrificing the appealing concept of product 'distance.' Copyright 1994 by The Review of Economic Studies Limited.

Journal Article Optimal Growth with Scale Economies in the Creation of Overhead Capital Get access M. L. Weitzman M. L. Weitzman Cowles Foundation Yale University Search for other works by this author on: Oxford Academic Google Scholar The Review of Economic Studies, Volume 37, Issue 4, October 1970, Pages 555–570, https://doi.org/10.2307/2296485 Published: 01 October 1970 Article history Received: 01 May 1969 Revision received: 01 December 1969 Published: 01 October 1970

This paper evaluates the loss of global welfare from exhaustion of nonrenewable resources, such as oil. The underlying methodology represents an empirical application of some recent developments in the theory of green accounting and sustainability. The paper estimates that the world loses the equivalent of about 1 percent of final consumption per year from finiteness of the earth's resources, compared with a counterfactual trajectory where global extraction of minerals is allowed to remain forever constant at today's flow rates and extraction costs.

This paper attempts to provide microfoundations for the knowledge production function in an idea-based growth model. Production of new ideas is made a function of newly reconfigured old ideas in the spirit of the way an agricultural research station develops improved plant varieties by cross-pollinating existing plant varieties. The model shows how knowledge can build upon itself in a combinatoric feedback process that may have significant implications for economic growth. The paper's main theme is that the ultimate limits to growth lie not so much in our ability to generate new ideas as in our ability to process an abundance of potentially new ideas into usable form.

This paper attempts to demonstrate how “diversity theory” can be applied to the analysis of real-world conservation policies. The specific example chosen to serve as a paradigm concerns preservation priorities among the fifteen species of cranes living wild throughout the world. The example is sufficiently actual to show how diversity theory can be used operationally to frame certain critical conservation questions and to guide us toward answers by providing informative quantitative indicators of what to protect. At the same time the cranes example is rich enough that it illustrates nicely some broad general principles about the economics of diversity preservation.

An oft-repeated goal in many contexts is the "preservation of diversity." But what is the diversity function to be optimized? This paper shows how a reasonable measure of the "value of diversity" of a collection of objects can be recursively generated from more fundamental information about the dissimilarity-distance between any pair of objects in the set. The diversity function is shown to satisfy a basic dynamic programming equation, which in a well-defined sense generates an optimal classification scheme. A surprisingly rich theory of diversity emerges, having ramifications for several disciplines. Implications and applications are discussed.