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Martin Shubik Publications

Publish Date
Abstract

In this paper we present a series of models, all within the context of a simple two-good economy, which bring out the distinctions between the different types of money and financial institutions. The models emphasize the physical properties of the economic goods, moneys, and trading systems. In Part 1 of the paper, we covered models in which the money is a consumable storable; here in Part 2 we consider economies using durable money, fiat money, or credit. Under this framework we are able to successfully contrast the role of private money lenders, banks, bilateral credit systems, and credit clearinghouses. We are also able to model the importance of the bankruptcy or default penalty in supporting the use of fiat.

Abstract

In this paper we present a series of models, all within the context of a simple two-good economy, which bring out the distinctions among the different types of money and financial institutions. The models emphasize the physical properties of the economic goods, moneys, and trading systems. Part 1 covers models in which the money is a consumable storable; the economies in Part 2 use durable money, fiat money, or credit. Under this framework we are able to successfully contrast the role of private money lenders, banks, bilateral credit systems, and credit clearinghouses. We are also able to model the importance of the bankruptcy or default penalty in supporting the use of fiat.

Abstract

A voting with absenteeism game is defined as a pair (G;r) where G is an n-player (monotonic) simple game and r is an n-vector for which ri is the probability that player i attends a vote. We define a power index for such games, called the absentee index. We axiomatize the absentee index and provide a multilinear extension formula for it. Using this analysis we re-derive Myerson’s (1977, 1980) “balanced contributions” property for the Shapley-Shubik power index. In fact, we derive a formula which quantitatively gives the amount of the ‘balanced contributions” in terms of the coefficients of the multilinear extension of the game.

Finally, we define the notion of substitutes and complements in simple games. We compare these concepts with the familiar concepts of dummy player, veto player, and master player.

Abstract

A simultaneous double auction market with bid and offer cards was utilized in classes on the theory and history of money and financial institutions and occasionally in classes on the theory of games. The prime purpose in using this game was to teach the students how to construct process models of economic phenomena. The second purpose was to consider the properties of the double auction market. The third purpose was to interpret the experimental results an link them to theory.

Abstract

Three variations of the core of a market game representing an exchange economy are considered and compared. The possibility for utilizing the Walrasian core to reflect certain monetary phenomena is noted.

Keywords: Market games, Strategic market game, Exchange economy, Core, Characteristic function

JEL Classification: C71, D5

Abstract

A simultaneous double auction market with bid and offer cards was utilized in classes on the theory and history of money and financial institutions and occasionally in classes on the theory of games. The prime purpose in using this game was to teach the students how to construct process models of economic phenomena. The second purpose was to consider the properties of the double auction market. The third purpose was to interpret the experimental results an link them to theory.

Keywords: Double auctions, Experimental games, Allocation games, Noncooperative equilibria

JEL Classification: C7, D44, C92, G1

Abstract

Arrow’s original proof of his impossibility theorem proceeded in two steps: showing the existence of a decisive voter, and then showing that a decisive voter is a dictator. Barbera replaced the decisive voter with the weaker notion of a pivotal voter, thereby shortening the first step, but complicating the second step. I give three brief proofs, all of which turn on replacing the decisive/pivotal voter with an extremely pivotal voter (a voter who by unilaterally changing his vote can move some alternative from the bottom of the social ranking to the top), thereby simplifying both steps in Arrow’s proof.

My first proof is the most straightforward, and the second uses Condorcet preferences (which are transformed into each other by moving the bottom alternative to the top). The third (and shortest) proof proceeds by reinterpreting Step 1 of the first proof as saying that all social decisions are made the same way (neutrality).

Abstract

The classical Fisher equation asserts that in a nonstochastic economy, the inflation rate must equal the difference between the nominal and real interest rates. We extend this equation to a representative agent economy with real uncertainty in which the central bank sets the nominal rate of interest. The Fisher equation still holds, but with the rate of inflation replaced by the harmonic mean of the growth rate of money. Except for logarithmic utility, we show that on almost every path the long-run rate of inflation is strictly higher than it would be in the nonstochastic world obtained by replacing output with expected output in every period. If the central bank sets the nominal interest rate equal to the discount rate of the representative agent, then the long-run rate of inflation is positive (and the same) on almost every path. By contrast, the classical Fisher equation asserts that inflation should then be zero. In fact, no constant interest rate will stabilize prices, even if the economy is stationary with bounded i.d.d. shocks. The central bank must actively manage interest rates if it wants to keep prices bounded forever. However, not even an active central bank can keep prices exactly constant.

Abstract

We introduce and justify a taxonomy for the structure of markets and minimal institutions which appear in constructing minimally complex trading structures to perform the functions of price formation, settlement and payments. Each structure is presented as a playable strategic market game and is examined for its efficiency, the number of degrees of freedom and the symmetry properties of the structure.

Abstract

In order to explain in a systematic way why certain combinations of market, financial, and legal structures may be intrinsic to certain capabilities to exchange real goods, we introduce criteria for abstracting the qualitative functions of markets. The criteria involve the number of strategic freedoms the combined institutions, considered as formalized strategic games, present to traders, the constraints they impose, and the symmetry with which those constraints are applied to the traders. We pay particular attention to what is required to make these “strategic market games” well-defined, and to make various solutions computable by the agents within the bounds on information and control they are assumed to have. As an application of these criteria, we present a complete taxonomy of the minimal one-period exchange economies with symmetric information and inside money. A natural hierarchy of market forms is observed to emerge, in which institutionally simpler markets are often found to be more suitable to fewer and less-diversified traders, while the institutionally richer markets only become functional as the size and diversity of their users gets large.

Abstract

We introduce and justify a taxonomy for the structure of markets and minimal institutions which appear in constructing minimally complex trading structures to perform the functions of price formation, settlement and payments. Each structure is presented as a playable strategic market game and is examined for its efficiency, the number of degrees of freedom and the symmetry properties of the structure.

Keywords: Strategic market games, Clearinghouses, Credit evaluation, Default

JEL Classification: C7, G10, G20, L10, D40, D50

Abstract

In order to explain in a systematic way why certain combinations of market, financial, and legal structures may be intrinsic to certain capabilities to exchange real goods, we introduce criteria for abstracting the qualitative functions of markets. The criteria involve the number of strategic freedoms the combined institutions, considered as formalized strategic games, present to traders, the constraints they impose, and the symmetry with which those constraints are applied to the traders. We pay particular attention to what is required to make these “strategic market games” well-defined, and to make various solutions computable by the agents within the bounds on information and control they are assumed to have. As an application of these criteria, we present a complete taxonomy of the minimal one-period exchange economies with symmetric information and inside money. A natural hierarchy of market forms is observed to emerge, in which institutionally simpler markets are often found to be more suitable to fewer and less-diversified traders, while the institutionally richer markets only become functional as the size and diversity of their users gets large.

Keywords: Strategic market games, Clearinghouses, Credit evaluation, Default

JEL Classification: C7, G10, G20, L10, D40, D50