2014/07/26 by N. Bagatella-Flores, M. Rodriguez-Achach, M. Rodrı́guez-Achach +3
Biochemistry, Genetics and Molecular Biology · Economics, Econometrics and Finance · Mathematics · Physics and Astronomy · Social Sciences · #Complex Systems and Time Series Analysis #Computer science #Distribution (mathematics) #Econometrics #Economic inequality #Economics #Econophysics #Evolution and Genetic Dynamics #Evolutionary Game Theory and Cooperation #Extreme value theory #Gini coefficient #Index (typography) #Inequality #Mathematical analysis #Mathematics #Perturbation (astronomy) #Physics #Quantum mechanics #Statistical physics #Statistics #physics.soc-ph #q-fin.GN
paper · pdf · doi:10.1016/j.physa.2014.07.081
15 pages, 5 figures. An Econophysics paper
arxiv created 2014/07/26 · openalex publication_date 2014/08/08 · arxiv updated 2015/06/22 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Punctuated Equilibrium (PE) states that after long periods of evolutionary quiescence, species evolution can take place in short time intervals, where sudden differentiation makes new species emerge and some species extinct. In this paper, we introduce and study the effect of punctuated equilibrium on two different asset exchange models: The yard sale model (YS, winner gets a random fraction of a poorer player's wealth) and the theft and fraud model (TF, winner gets a random fraction of the loser's wealth). The resulting wealth distribution is characterized using the Gini index. In order to do this, we consider PE as a perturbation with probability ρ of being applied. We compare the resulting values of the Gini index at different increasing values of ρ in both models. We found that in the case of the TF model, the Gini index reduces as the perturbation ρ increases, not showing dependence with the agents number. While for YS we observe a phase transition which happens around ρc=0.79. For perturbations ρ<ρc the Gini index reaches the value of one as time increases (an extreme wealth condensation state), whereas for perturbations bigger or equal than ρc the Gini index becomes different to one, avoiding the system reaches this extreme state. We show that both simple exchange models coupled with PE dynamics give more realistic results. In particular for YS, we observe a power low decay of wealth distribution.