arXiv subjects

Lautaro Giordano

Publications and source records attributed to Lautaro Giordano.

3 recordsLinked to original sources

arXiv2026

Phase Transitions in Economic Inequality:Taxation and Extremal Replacement Dynamics

We present a minimal agent-based model of interacting agents characterized by their wealth to study taxation and inequality in a non-conservative economy. Wealth evolves through an extremal stochastic replacement process in which the poorest agent has its wealth replaced by a new random value, financed through a collective taxation mechanism. We explore taxation regimes ranging from regressive to progressive schemes and tune the overall redistribution strength. Under regressive taxation, the system self-organizes into two distinct stationary phases when changing the total tax collected: a non-ergodic, high-inequality regime characterized by wealth condensation in a subset of agents that permanently escape replacement, and a more homogeneous ergodic phase in which all agents participate in the dynamics. Increasing taxes drives an abrupt transition between these phases. The transition is discontinuous and exhibits hysteresis and bistability, consistently detected through the Gini index, the Top $1\%$ wealth share, the entropy, and the Binder cumulant. In contrast, neutral and progressive taxation suppress persistent wealth concentration, preventing the emergence of strongly unequal states and eliminating hysteretic behavior. We complement the simulations with a parameter-free mean-field theory of the wealth dynamics that reproduces the stationary distributions and explains the transition by locating the two spinodals that bound the bistable region. These results show that minimal stochastic redistribution mechanisms alone can produce discontinuous transitions, metastability, and non-ergodicity, demonstrating that taxation structure can determine the emergence and stability of macroscopic inequality.

physics.soc-ph↗

arXiv2025

Limiting risk to reduce inequality: insights from the Yard-Sale model

Wealth inequality remains a critical socioeconomic challenge, driven by systemic dynamics and self-reinforcing mechanisms that amplify the economic imbalances. Simplified models from statistical physics provide valuable insights into the fundamental mechanisms governing wealth distribution. In this study, we extend the Yard-Sale model -- a minimal kinetic exchange framework -- to investigate how limiting risk in economic transactions affects inequality. While previous research demonstrates that such models naturally lead to wealth concentration, we introduce a mechanism that restricts the maximum risk agents can assume during exchanges. Numerical simulations reveal that this modification fosters more equitable wealth distributions and significantly reduces extreme disparities. These findings highlight the importance of individual-level constraints in shaping systemic outcomes, offering new perspectives on promoting economic balance.

physics.soc-ph↗

arXiv2025

Wealth Inequality in Agent-Based Economies: The Dominant Role of Social Protection over Growth

Persistent wealth inequality, where a small fraction of the population accumulates most resources while the majority remains economically vulnerable, is a widespread phenomenon. We investigate its underlying mechanisms using an agent-based Yard-Sale model that incorporates two complementary features: transaction rules that favor poorer agents, representing social protection policies, and an economic growth process with explicit wealth redistribution. Our results reveal that social protection plays a dominant role in reducing inequality, while redistribution primarily serves to reintegrate excluded agents. These findings suggest that social protection policies, that is, targeted mechanisms favoring economically vulnerable agents, may have a substantially greater impact on reducing inequality than redistribution driven solely by economic growth. We also find that both the shape of the wealth distributions and the resulting inequality levels are strongly influenced by the underlying distribution of individual risk, highlighting the importance of considering agent heterogeneity when modeling economic dynamics.

physics.soc-ph↗