Láthatóvá teheto-e a láthatatlan kéz? Egy ágensalapú piaci modell tapasztalatai

Economic theory tends to consider market mechanisms as equilibrium systems, in which reaching equilibrium is at most a matter of time. This view, however, is based on a set of strong assumptions: (i) the explicit appearance of an "invisible hand" in the form of the Walrasian auctioneer, excluding transactions inconsistent with the equilibrium, (ii) rational behaviour by the actors, (iii) perfect information. In addition, macro-level analyses heavily build on the assumptions of (iv) homogeneity among the actors (representative agents), and (v) separating the price and quantity-adjustment mechanisms. As real market circumstances hardly satisfy these assumptions, the stability of market mechanisms is questionable. This paper builds an agent-based model, designed to trace market dynamics when these assumptions are not met. With this bottom-up model, the authors analyse the effect of market micro-structures and decision mechanisms on the equilibrium processes of the market. The research showed that (i) the number of market actors has a strong effect on adjustment processes even if they are homogenous, (ii) price and quantity considerations in the decision-making rules do not have a significant effect on the market price or quantity, (iii) broadening information flows enhances market adjustment, and (iv) heterogeneity has a sounder effect if producers are heterogeneous. [PUBLICATION ABSTRACT]