Weighted Trade Network in a Model of Preferential Bipartite Transactions

TL;DR

This paper models a wealth distribution system with preferential bipartite trading, resulting in a heterogeneous, scale-free trade network that exhibits non-trivial correlations and a robust Pareto wealth distribution.

Contribution

It introduces a tunable preferential selection rule in a wealth exchange model, revealing continuous changes in network properties while maintaining a Pareto wealth distribution.

Findings

Trade network is scale-free with heterogeneous degree and weight distributions.

Critical exponents vary continuously with tuning parameters.

Wealth distribution follows Pareto law for all positive parameters.

Abstract

Using a model of wealth distribution where traders are characterized by quenched random saving propensities and trade among themselves by bipartite transactions, we mimic the enhanced rates of trading of the rich by introducing the preferential selection rule using a pair of continuously tunable parameters. The bipartite trading defines a growing trade network of traders linked by their mutual trade relationships. With the preferential selection rule this network appears to be highly heterogeneous characterized by the scale-free nodal degree and the link weight distributions and presents signatures of non-trivial strength-degree correlations. With detailed numerical simulations and using finite-size scaling analysis we present evidence that the associated critical exponents are continuous functions of the tuning parameters. However the wealth distribution has been observed to follow the well-known Pareto law robustly for all positive values of the tuning parameters.