General equilibrium without utility functions: how far to go?

How far can we go in weakening the assumptions of the general equilibrium model? Existence of equilibrium, structural stability and finiteness of equilibria of regular economies, genericity of regular economies and an index formula for the equilibria of regular economies have been known not to require transitivity and completeness of consumers’ preferences. We show in this paper that if consumers’ non-ordered preferences satisfy a mild version of convexity already considered in the literature, then the following properties are also satisfied: (1) the smooth manifold structure and the diffeomorphism of the equilibrium manifold with a Euclidean space; (2) the diffeomorphism of the set of no-trade equilibria with a Euclidean space; (3) the openness and genericity of the set of regular equilibria as a subset of the equilibrium manifold; (4) for small trade vectors, the uniqueness, regularity and stability of equilibrium for two version of tatonnement; (5) the pathconnectedness of the sets of stable equilibria.     

Budget share and optimal commodity taxes without computation

This paper shows for the linear expenditure system that the optimal tax rates increase across commodities in the ratio of the respective budget shares of the rich to those of the poor—i.e., the more luxurious good has a higher tax. These budget shares can be calculated either at pre-tax or post-tax price levels, thus can be expressed directly in terms of the basic parameters of the linear expenditure system.     

Search in cities

The aim of this paper is to expose the recent developments of urban search models which incorporate a land market into a search-matching framework. Using these models, we will be able to explain why unemployment rates vary within a city, how city structure affects workers’ labor-market outcomes, how unemployment benefits and the job-destruction rate affect the growth of cities and why workers living far away from job centers search less intensively and experience higher unemployment rates than those residing closer to jobs. We are also able to explain why, as compared to whites, black workers spend more time commuting to work but travel less miles and search for jobs over a smaller area.     

Optimal Licensing Contracts and the Value of a Patent

We extend Kamien and Tauman's (1986) analysis of the value of a patent. We find that an inventor can always design a fixed fee plus royalty contract such that his revenue is equal to the profit a monopoly endowed with the innovation could make on the market. This implies that the social value of a patent can be strictly negative whenever the patented innovation is of bad quality. We also explain why a principal can have an interest in using performance-based contracts although the principal and the agents are risk-neutral, information is symmetric, and agents' actions are verifiable.     

Centralized and decentralized control polices for a two-stage stochastic supply chain with subcontracting

An analysis of control policies for a two-stage supply chain with subcontractors at each stage is presented when decisions at each stage concerning safety stocks, backorders, and subcontracting are made jointly or in a decentralized manner. The inventory/admission control policies considered are base stock, echelon base stock and partial backordering, and the objective is to maximize the mean profit rate of the system. The optimal control parameters are found by exhaustive search using Markov chains. From numerical examples it appears that the policies which manage jointly sales and production levels in each stage provide much higher overall (system) profits than decentralized policies, although the latter are individually more profitable for the second stage. In addition, partial backordering provides the system with an extra profit above those that result from the lost sales (no backordering) and complete backordering policies. Finally, a number of numerical results show the impact of variations in certain system parameters on the optimal control parameters and the corresponding profit.     

The idea of reproduction

The concept of social reproduction which helps to identify elements and relations decisive for a transition from one social formation to another is presented here as a contribution to the methodology of social forecasting. The theoretical schema is constructed and tested in a retrospective forecasting exercise. The same methods are then applied to qualify the elements of change in contemporary society.