Gang confrontation: The case of Medellin (Colombia)

Protracted conflict is one of the largest human challenges that have persistently undermined economic and social progress. In recent years, there has been increased emphasis on using statistical and physical science models to better understand both the universal patterns and the underlying mechanics of conflict. Whilst macroscopic power-law fractal patterns have been shown for death-toll in wars and self-excitation models have been shown for roadside ambush attacks, very few works deal with the challenge of complex dynamics between gangs at the intra-city scale. Here, based on contributions to the historical memory of the conflict in Colombia, Medellin’s gang-confrontation-network is presented. It is shown that socio-economic and violence indexes are moderate to highly correlated to the structure of the network. Specifically, the death-toll of conflict is strongly influenced by the leading eigenvalues of the gangs’ conflict adjacency matrix, which serves a proxy for unstable self-excitation from revenge attacks. The distribution of links based on the geographic distance between gangs in confrontation leads to the confirmation that territorial control is a main catalyst of violence and retaliation among gangs. As a first attempt to explore the time evolution of the confrontation network, the Boltzmann-Lotka-Volterra (BLV) dynamic interaction network analysis is applied to quantify the spatial embeddedness of the dynamic relationship between conflicting gangs in Medellin. However, the non-stationary character of the violence in Medellin during the observation period restricts the application of the BLV model and results suggest that more involved and comprehensive models are needed to described the dynamics of Medellin’s armed conflict.

持久冲突是长期破坏经济与社会进步的最重大人类挑战之一。近年来，学界愈发重视借助统计与物理科学模型，以更深入地理解冲突的普适模式与内在作用机制。尽管已有研究证实战争中的死亡人数呈现宏观幂律分形模式，路边伏击袭击存在自激发模型，但极少有研究聚焦城市内部尺度下帮派间的复杂动态关系这一难题。基于对哥伦比亚冲突历史记忆的相关研究贡献，本文呈现了麦德林帮派对抗网络数据集。研究表明，社会经济与暴力指数与该网络的结构呈中度至高度相关。具体而言，冲突死亡人数受帮派冲突邻接矩阵（adjacency matrix）的主导特征值强烈影响，而该特征值可作为报复性袭击引发不稳定自激发现象的代理指标。基于对抗帮派间地理距离构建的连边分布，证实了领土控制是帮派间暴力与报复行为的核心催化剂。作为探索对抗网络时间演化的首次尝试，本文采用玻尔兹曼-洛特卡-沃尔泰拉（Boltzmann-Lotka-Volterra, BLV）动态交互网络分析方法，量化麦德林对立帮派间动态关系的空间嵌入性。然而观测期内麦德林暴力事件的非平稳特性限制了BLV模型的应用效果，研究结果表明，需构建更具包容性与综合性的模型，方能刻画麦德林武装冲突的动态演化过程。