Complexity

While the individual man is an insoluble puzzle, in the aggregate he becomes a mathematical certainty. You can, for example, never foretell what any one man will do, but you can say with precision what an average number will be up to. Individuals vary, but percentages remain constant. So says the statistician Sherlock Holmes in “The Sign of Four”. Via Gaussianos

Authors: Fabrizio Lillo, Esteban Moro, Gabriella Vaglica y Rosario Mantegna Journal: New Journal of Physics 10 (2008) 043019 LINK arXiv Abstract: Agent-based models of financial markets usually make assumptions about agent’s preferred stylized strategies. Empirical validations of these assumptions have not been performed so far on a full-market scale. Here we present a comprehensive study of the resulting strategies followed by the firms which are members of the Spanish Stock Exchange. ...

Authors: Gabriella Vaglica, Fabrizio Lillo, Esteban Moro y Rosario N. Mantegna Journal: Physical Review E 77, 036110 (2008). LINK | arXiv Abstract: The dynamics of many socioeconomic systems is determined by the decision making process of agents. The decision process depends on agent’s characteristics, such as preferences, risk aversion, behavioral biases, etc. In addition, in some systems the size of agents can be highly heterogeneous leading to very different impacts of agents on the system dynamics. ...