HAHN, SANGSUB; PHD

                         UNIVERSITY OF PITTSBURGH, 1992
 
                         ECONOMICS, THEORY (0511)
 

                         In this dissertation, we first consider a dynamic general equilibrium model in which stochastic
                         technological innovations generated through R&D take place in the form of technological advances. This
                         new technology, in turn, can directly reduce the unit cost for a continuum of consumption goods or a
                         continuum of intermediate goods by lowering the quantity of inputs required to produce one unit of each
                         good. Steady-state equilibrium and optimal growth rates are derived, and sources of discrepancies
                         between these rates are examined. The basic models considered above are extended in two different
                         ways; (1) the long-run affects of domestic taxation on economic growth and welfare are explored formally
                         by introducing a government sector; (2) the growth and welfare affects of openness to international trade
                         and tariff policies are examined by incorporating a two-country setting featuring international trade. We
                         next analyze the impact of external learning by doing on economic growth by extending the models
                         proposed by Romer (1990, 1991b): models with and without knowledge spillovers are considered. In
                         both models, steady-state equilibrium and optimal growth rates are derived and the relationship between
                         both rates are examined. We explore the effects of external learning by doing on the growth patterns of
                         developed and developing countries. We also analyze the long-run affects of taxation on economic
                         growth by introducing a government sector, from which we derive policy implications of taxation for
                         economic growth. Finally, we extend Grossman and Helpman's (1991c) model in order to examine the
                         impact of knowledge diffusion (within-country and across-country) and Southern learning by doing on
                         world economic growth and the endogenous rates of Northern innovation and Southern imitation in a
                         North-South international trade setting. Under extensions made here, the steady-state rates of the world
                         economic growth, and Northern innovation and Southern imitation are derived. Based upon these
                         results, we examine the impact of knowledge diffusion and Southern learning by doing on the
                         performance of the world economy.

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