Network cohesion
定义了一种网络凝聚力度量，并展示其在具有网络外部性的内生增长模型中自然出现，证明凝聚力越高，条件收敛速度越快。
We define a measure of network cohesion and show how it arises naturally in a broad class of dynamic models of endogenous perpetual growth with network externalities. Via a standard growth model, we show why network cohesion is crucial for conditional convergence and explain that as cohesion increases, convergence is faster. We prove properties of network cohesion and define a network aggregator that preserves network cohesion.