Convergence and Hardness of Strategic Schelling Segregation
Convergence and Hardness of Strategic Schelling Segregation
复制标题
战略谢林分离的收敛性和硬度
DOI:
10.1007/978-3-030-35389-6_12
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发表时间:
2019
期刊:
影响因子:
--
通讯作者:
David Stangl
中科院分区:
文献类型:
--
作者:
Hagen Echzell;T. Friedrich;Pascal Lenzner;Louise Molitor;Marcus Pappik;Friedrich Schöne;Fabian Sommer;David Stangl
The phenomenon of residential segregation was captured by Schelling's famous segregation model where two types of agents are placed on a grid and an agent is content with her location if the fraction of her neighbors which have the same type as her is at least $\tau$, for some $0<\tau<1$. Discontent agents simply swap their location with a randomly chosen other discontent agent or jump to a random empty cell.
We analyze a generalized game-theoretic model of Schelling segregation which allows more than two agent types and more general underlying graphs modeling the residential area. For this we show that both aspects heavily influence the dynamic properties and the tractability of finding an optimal placement. We map the boundary of when improving response dynamics (IRD), i.e., the natural approach for finding equilibrium states, are guaranteed to converge. For this we prove several sharp threshold results where guaranteed IRD convergence suddenly turns into the strongest possible non-convergence result: a violation of weak acyclicity. In particular, we show such threshold results also for Schelling's original model, which is in contrast to the standard assumption in many empirical papers. Furthermore, we show that in case of convergence, IRD find an equilibrium in $\mathcal{O}(m)$ steps, where $m$ is the number of edges in the underlying graph and show that this bound is met in empirical simulations starting from random initial agent placements.