Irving Fisher’s Ph.D. thesis, submitted to Yale University in 1891, contains a fully articulated general equilibrium model presented with the broad scope and formal mathematical clarity associated with Walras and his successors. In addition, Fisher presents a remarkable hydraulic apparatus for calculating equilibrium prices and the resulting distribution of society’s endowments among the agents in the economy. In this paper we provide an analytical description of Fisher’s apparatus, and report the results of simulating the mechanical/hydraulic “machine,” illustrating the ability of the apparatus to “compute” equilibrium prices and also to find multiple equilibria.
Portfolio theory has been an important component of open economy macroeconomic models. In those models, it is essential to distinguish among several categories of assets, both foreign and domestic, and to specify the demands and supplies. This framework has become increasingly relevant. Movements of capital across regional and national boundaries, and across currencies, have exploded in volume, thanks to the dismantling of currency and exchange controls and other financial regulations and to revolutionary economies in technologies of communication and transactions. The globalization of financial markets was stimulated by the floating exchange rate regime established in 1973.
Keywords: Portfolio choice, open economy, capital mobility, exchange rate