1,446 research outputs found
Harms and benefits from social imitation
We study the role of imitation within a model of economics with adaptive
agents. The basic ingredients are those of the Minority Game. We add the
possibility of local information exchange and imitation of the neighbour's
strategy. Imitators should pay a fee to the imitated. Connected groups are
formed, which act as if they were single players. Coherent spatial areas of
rich and poor agents result, leading to the decrease of local social tensions.
Size and stability of these areas depends on the parameters of the model.
Global performance measured by the attendance volatility is optimised at
certain value of the imitation probability. The social tensions are suppressed
for large imitation probability, but due to the price paid by the imitators the
requirements of high global effectivity and low social tensions are in
conflict, as well as the requirements of low global and low local wealth
differences.Comment: 11 pages, elsart style, to appear in the proceedings of NATO ARW on
Application of Physics in Economic Modelling, Prague, 8-10 February 200
Self-organized branching process for a one-dimensional ricepile model
A self-organized branching process is introduced to describe one-dimensional
ricepile model with stochastic topplings. Although the branching processes are
generally supposed to describe well the systems in high dimension, our
modification grasps some of the peculiarities present in one dimension. We find
analytically the crossover behavior from the trivial one-dimensional BTW
behavior to self-organized criticality characterized by power-law distribution
of avalanches. The finite-size effects, which are crucial in the crossover, are
calculated.Comment: 8 pages, 1 figure; an error corrected in this versio
On the possibility of optimal investment
We analyze the theory of optimal investment in risky assets, developed
recently by Marsili, Maslov and Zhang [Physica A 253 (1998) 403]. When the real
data are used instead of abstract stochastic process, it appears that a
non-trivial investment strategy is rarely possible. We show that non-zero
transaction costs make the applicability of the method even more difficult. We
generalize the method in order to take into account possible correlations in
the asset price.Comment: 6 pages, 5 figures, submitted to Physica
Analytical results for the Sznajd model of opinion formation
The Sznajd model, which describes opinion formation and social influence, is
treated analytically on a complete graph. We prove the existence of the phase
transition in the original formulation of the model, while for the Ochrombel
modification we find smooth behaviour without transition. We calculate the
average time to reach the stationary state as well as the exponential tail of
its probability distribution. An analytical argument for the observed
dependence in the distribution of votes in Brazilian elections is provided.Comment: 10 pages 5 figure
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