
on Network Economics 
By:  Yiduo Huang; Zuojun Max Shen 
Abstract:  The recovery of the public transportation system is critical for both social reengagement and economic rebooting after the shutdown during pandemic like COVID19. In this study, we focus on the integrated optimization of service line reopening plan and timetable design. We model the transit system as a spacetime network. In this network, the number of passengers on each vehicle at the same time can be represented by arc flow. We then apply a simplified spatial compartmental model of epidemic (SCME) to each vehicle and platform to model the spread of pandemic in the system as our objective, and calculate the optimal open plan and timetable. We demonstrate that this optimization problem can be decomposed into a simple integer programming and a linear multicommodity network flow problem using Lagrangian relaxation techniques. Finally, we test the proposed model using realworld data from the Bay Area Rapid Transit (BART) and give some useful suggestions to system managers. 
Date:  2021–09 
URL:  http://d.repec.org/n?u=RePEc:arx:papers:2109.03940&r= 
By:  Marcin P\k{e}ski 
Abstract:  We study binary coordination games with random utility played in networks. A typical equilibrium is fuzzy  it has positive fractions of agents playing each action. The set of average behaviors that may arise in an equilibrium typically depends on the network. The largest set (in the set inclusion sense) is achieved by a network that consists of a large number of copies of a large complete graph. The smallest set (in the set inclusion sense) is achieved on a latticetype network. It consists of a single outcome that corresponds to a novel version of risk dominance that is appropriate for games with random utility. 
Date:  2021–08 
URL:  http://d.repec.org/n?u=RePEc:arx:papers:2108.13474&r= 
By:  Roy Cerqueti; Giulia Rotundo; Marcel Ausloos 
Abstract:  In this work, we develop the Tsallis entropy approach for examining the crossshareholding network of companies traded on the Italian stock market. In such a network, the nodes represent the companies, and the links represent the ownership. Within this context, we introduce the outdegree of the nodes  which represents the diversification  and the indegree of them  capturing the integration. Diversification and integration allow a clear description of the industrial structure formed by the considered companies. The stochastic dependence of diversification and integration is modelled through copulas. We argue that copulas are well suited for modelling the joint distribution. The analysis of the stochastic dependence between integration and diversification by means of the Tsallis entropy gives a crucial information on the reaction of the market structure to the external shocks,  on the basis of some relevant cases of dependence between the considered variables. In this respect, the considered entropy framework provides insights on the relationship between indegree and outdegree dependence structure and market polarisation or fairness. Moreover, the interpretation of the results in the light of the Tsallis entropy parameter gives relevant suggestions for policymakers who aim at shaping the industrial context for having high polarisation or fair joint distribution of diversification and integration. Furthermore, a discussion of possible parametrisations of the indegree and outdegree marginal distribution,  by means of power laws or exponential functions,  is also carried out. An empirical experiment on a large dataset of Italian companies validates the theoretical framework. 
Date:  2021–08 
URL:  http://d.repec.org/n?u=RePEc:arx:papers:2109.04214&r= 