This paper develops a discussion and provides the basis for a dispute of the principal assumption on which the classical-neoclassical theory of perfect competition is based: is it indeed true that the individual product demand of each producer is perfectly elastic (horizontal) and the price is...

During the second half of the twentieth century economic theory moved increasingly away from price theory, which was gradually displaced by more modern trends such as game theory, decision theory, behavioral-empirical-experimental economics, heterodox economics, etc. This was due to serious...

I demonstrate a straightforward but apparently widely unrecognized implication of the standard requirements for perfect competition: an economy in which consumers can choose to learn is generally not perfectly competitive. In particular, if endogenous welfare relevant learning is feasible, the...

This paper studies an exchange economy with a finite number of agents in which each agent is initially endowed with a finite number of (personalized) indivisible commodities. We observe that the core equivalence theorem may not hold for this economy when the coalitional form game is generated in...

We present comprehensive evidence in support of giving liquidity equal standing to size, value/growth, and momentum as investment styles, as defined by Sharpe (1992). First, we show that financial market liquidity, as identified by stock turnover, is an economically significant indicator of...

I propose an arbitrage-based theory of bubbles in economies with general portfolio constraints and differences in beliefs. I find that, in general, bubbles cannot exist unless the constraints restrict the demand for credit sufficiently to induce low interest rates. Speculation due to...

In his seminal paper on arbitrage and competitive equilibrium in unbounded exchange economies, Werner (Econometrica, 1987) proved the existence of a competitive equilibrium, under a price no-arbitrage condition, without assuming either local or global nonsatiation. Werner's existence result...

Many consumers care about climate change and other externalities associated with their purchases. We analyze the behavior and market effects of such "socially responsible consumers" in three parts. First, we develop a flexible theoretical framework to study competitive equilibria with rational...

We investigate how price ceilings and floors affect outcomes in continuous time, double auction markets with discrete goods and multiple qualities. When price controls exist, the existence of competitive equilibria (the solution concept of classical market theory) is no longer guaranteed; hence, we...

We show how frictions and continuous transfers jointly affect equilibria in a model of matching in trading networks. Our model incorporates distortionary frictions such as transaction taxes, bargaining costs, and incomplete markets. When contracts are fully substitutable for firms, competitive...