In this paper we present a simple and unified model in which a large variety of politico-economic systems may be represented and static comparisons, positive and normative, between these systems may be carried out. In principle, the model encompasses an infinite variety of political economies, but we focus on twelve salient cases, namely, five types of capitalism, two types of communism, two types of slavery, and three types of colonialism.

In § 1 we introduce our approach, specify the basic data (preferences and technology) we will be working with, and assemble the « nutshell » within which we will remain from there on. In § 2 we describe a dozen political economies and determine, for each, both their associated « positive » economic quantities, such as employment and output and the distribution of income between workers, capitalists and colonialists, as well as corresponding magnitudes, such as « communal surplus » and class members' utility levels, which form the basis for our analysis in the subsequent sections. All these are displayed as Table I, and the outcomes of the dozen political economies considered are identified in Figure I, which depicts the « nutshell » assembled in § 1. Then § 3 derives the preferences of workers, capitalists and colonialists (displayed in Diagrams I, II and III, resp.) regarding the politico-economic systems in question, determining a class conflict which arises, identifying the Pareto-efficient systems for all the coalitions of classes. In § 4 we rank our dozen political economies in terms of the respective communal surplus they generate, from which it becomes plain in which « revolutions » (changes in politico-economic systems) the winners may compensate the losers. Finally, § 5 closes our present study by indicating how it might be fruitfully extended.

Two distinct models of rational economic behaviour may be useful in explaining an apparent change in the relationship between short-term US interest rates and the US money supply. These models are implicit in the recent rational expectations literature which includes Lucas (1972), Fischer (1977), Phelps and Taylor (1977), Poole (1976) and Sargent and Wallace (1975). Yet, the two models give flatly contradictory results.

In the first model, the market is rational because it understands how policy makers, particularly the monetary authorities, behave and forecasts future monetary policy with some degree of accuracy. When the money growth rate rises above target in the United States, for example, market participants forecast a future increase in the Federal Funds rate aimed at slowing growth of the money stock in some future period. In this case the monetary authority is monetarist but the market need not be. The authorities believe that inflation is a monetary phenomenon and the money stock is controlled to achieve a desired inflation rate. The market need only understand how the monetary authority behaves.

Durant les trente dernières années, les regroupements d’entreprises furent partie intégrante du développement des économies capitalistes. Beaucoup d’études visèrent à analyser leur impact sur la structure des marchés, et sur certaines variables macro-économiques (R. NELSON (1959), G.J. STIGLER (1950)). Cependant peu essayèrent de répondre aux questions qui suivent : quelles sont les firmes qui se sont faites absorber? Sontelles différentes de celles qui survivent? Peut-on prévoir l’absorption d’une société à l’aide de données économiques et financières? C’est à ces questions que le présent article va essayer de répondre. Plusieurs milliers de firmes françaises ayant subi ce sort depuis 1962, il est important de connaître la nature de ce processus, afin de savoir s’il a favorisé la réalisation d’une meilleure allocation de ressources en pénalisant les firmes peu efficaces.

Après avoir présenté succinctement dans une première section les diverses théories en présence, nous aborderons dans une seconde section les problèmes relatifs à la construction d'un modèle permettant de tester ces hypothèses, une troisième section étant consacrée à l'interprétation des résultats des tests mis en place.