SIMPLE MODELS FOR COMPLEX SYSTEMS – TOYS OR TOOLS?

Katarzyna Sznajd-Weron

Wroclaw University of Science and Technology
The talk is thought of as a personal journey through the wonderful world of simple models designed to describe complex systems. I am not going to make a review, neither talk about the most important models. Instead I will present models and papers that influenced my scientific work, brought me new ideas or surprised me. My talk will be divided into three parts. In the first part I will present simple models of biological evolution and population dynamics. Among them the seminal Bak-Seppen model, particularly important from my perspective. In the second part I will talk about interactions between physics and social sciences. I will start from the history of sociology and “social physics”, next introduce several simple models of societies. I will try to answer the question whether they should be regarded as tools or as toys. Finally, in the last part, I will address the question: Can people be treated as particles? I will present several social experiments and show how the results of these experiments were used to build a simple model of opinion dynamics, known as the Sznajd model. Something to read:
  1. P. Bak and K. Sneppen, “Punctuated equilibrium and criticality in a simple model of evolution.” Phys. Rev. Lett. 71, 4083–4086. 1993.
  2. M. E. J. Newman and R. G. Palmer “Models of Extinction. A Review”, arXiv:adap-org/9908002v1 6 Aug 1999
  3. Philip Ball “The physical modeling of society: a historical perspective”, Physica A 314 (2002) 1 – 14
  4. Claudio Castellano, Santo Fortunato and Vittorio Loreto “Statistical physics of social dynamics”, Reviews of Modern Physics, Volume 81, April–June 2009

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