Optimal Firm Behaviour In The Context Of Technological Progress And A Business Cycle

This thesis is a theoretical study of the optimal dynamic policies of a, to some extent, slowly adjusting firm that faces an exogeneously given technological progress and an exogeneously given business cycle. It belongs to the area of mathematical economics. It is intended to appeal to mathematical economists in the first place, economists in the second place and mathematicians in the third place. It entails an attempt to stretch the limits of the application of deterministic dynamic optimisation to economics, in particular to firm behaviour. A well-known· Dutch economist (and trained mathematician) recently stated in 1 a local university newspaper that mathematical economists give economics a bad reputation, since they formulate their problems from a mathematical point of view and they are only interested in technical, mathematical problems. At the same time, however, "profound as economists may be, when it comes to extending or modifying the existing theory to make it applicable to a certain economic problem, an understanding of optimal control theory (which is the mathematical theory used in this thesis, ovh) based solely on heuristic arguments will often turn out to be inadequate" (SydS

This book contributes to the scientific field of optimal control theory applied to dynamic models of the firm. It discusses optimal investment, financing and production policies of the firm, that have to deal with a variety of aspects, such as financial constraints, start-up costs, business cycles, increasing returns to scale, production life cycles and experience curves. In contrast to many other publications on this subject, here, in combination with an analytical approach, the dynamic optimization problems are solved numerically with the aid of a powerful computer and specific programs for optimizing non-linear functions of a finite number of variables and non-linear constraints.

The main objective of this volume is to provide a presentation and discussion of recent developments in optimization and related fields. Equal emphasis is given to theoretical and practical studies. All the papers in this volume contain original results except two of them which are survey contributions. They deal with a wide range of topics such as optimization and variational inequalities, sensitivity and stability analysis, control theory, convex and nonsmooth analysis, and numerical methods.

My interest in microsimulation started to develop when I was exposed to the works of Guy Orcutt and his associates on microsimulation of households in the USA, and those of Gunnar Eliasson and his associates on simulatio~ of Swedish firms. Their approaches promised the exciting possibility to represent an by simulating the behaviour of individual microeconomic entire economic system units on a computer. The construction of a large scale microsimulation model seemed to be a worthwhile adventure which could yield much more detailed results than existing models. It was also evident that microsimulation of firms is a relatively underdeveloped area, in spite of the large number of operational microsimulation models of households in the USA and Europe. Developing the computer implementation has been an integral part of the research. Translating initially vague ideas into mathematical formulae and subsequently into a structured computer language provides a testing ground for 10Bical consistency of ideas. When writing this book I have purposefully abstained from describing the computer program and dedicated solution algorithms. The reason is that the book is primarily directed towards readers interested in economics and therefore uses the language of economics and not that of computer science. The simulation model has been programmed for the personal computer in Turbo Pascal. Sophisticated memory management techniques have lifted constraints on the number of firms which can be simulated on the PC.

Over more than two centuries the developmentofeconomic theory has created a wide array of different concepts, theories, and insights. My recent books, Capital and Knowledge (Zhang, 1999) and A TheoryofInternational Trade (Zhang, 2000) show how separate economic theories such as the Marxian economics, the Keynesian economics, the general equilibrium theory, the neoclassical growth theory, and the neoclassical trade theory can be examined within a single theoretical framework. This book isto further expand the frameworkproposed in the previous studies. This book is a part of my economic theory with endogenous population, capital, knowledge, preferences, sexual division of labor and consumption, institutions, economic structures and exchange values over time and space (Zhang, 1996a). As an extension of the Capital and Knowledge, which is focused on the dynamics of national economies, this book is to construct a theory of urban economies. We are concerned with dynamic relations between division of labor, division ofconsumption and determination of prices structure over space. We examine dynamic interdependence between capital accumulation, knowledge creation and utilization, economicgrowth, price structuresand urban pattern formation under free competition. The theory is constructed on the basisofa few concepts within a compact framework. The comparative advantage of our theory is that in providing rich insights into complex of spatial economies it uses only a few concepts and simplified functional forms and accepts a few assumptions about behavior of consumers, producers, and institutionalstructures.

The papers collected in this volume are contributions to T.I.Tech./K.E.S. Conference on Nonlinear and Convex Analysis in Economic Theory, which was held at Keio University, July 2-4, 1993. The conference was organized by Tokyo Institute of Technology (T. I. Tech.) and the Keio Economic Society (K. E. S.) , and supported by Nihon Keizai Shimbun Inc .. A lot of economic problems can be formulated as constrained optimiza tions and equilibrations of their solutions. Nonlinear-convex analysis has been supplying economists with indispensable mathematical machineries for these problems arising in economic theory. Conversely, mathematicians working in this discipline of analysis have been stimulated by various mathematical difficulties raised by economic the ories. Although our special emphasis was laid upon "nonlinearity" and "con vexity" in relation with economic theories, we also incorporated stochastic aspects of financial economics in our project taking account of the remark able rapid growth of this discipline during the last decade. The conference was designed to bring together those mathematicians who were seriously interested in getting new challenging stimuli from economic theories with those economists who were seeking for effective mathematical weapons for their researches. Thirty invited talks (six of them were plenary talks) given at the conf- ence were roughly classified under the following six headings : 1) Nonlinear Dynamical Systems and Business Fluctuations, . 2) Fixed Point Theory, 3) Convex Analysis and Optimization, 4) Eigenvalue of Positive Operators, 5) Stochastic Analysis and Financial Market, 6) General Equilibrium Analysis.

The 9th Belgian-French-German Conference on Optimization has been held in Namur (Belgium) on September 7-11, 1998. This volume is a collection of papers presented at this Conference. Originally, this Conference was a French-German Conference but this year, in accordance with the organizers' wishes, a third country, Belgium, has joined the founding members of the Conference. Hence the name: Belgian French-German Conference on Optimization. Since the very beginning, the purpose of these Conferences has been to bring together researchers working in the area of Optimization and partic ularly to encourage young researchers to present their work. Most of the participants come from the organizing countries. However the general ten dancy is to invite outside researchers to attend the meeting. So this year, among the 101 participants at this Conference, twenty researchers came from other countries. The general theme of the Conference is everything that concerns the area of Optimization without specification of particular topics. So theoretical as pects of Optimization, in addition to applications and algorithms of Opti mization, will be developed. However, and this point was very important for the organizers, the Conference must retain its convivial character. No more than two parallel sessions are organized. This would allow useful contacts between researchers to be promoted. The editors express their sincere thanks to all those who took part in this Conference. Their invaluable discussions have made this volume possible.