taking an (irreversible) action. We define \textit{asymptotic learning} as the fraction of agents taking the correct action … converging to one as a society grows large. Under truthful communication, we show that asymptotic learning occurs if (and under … ``information hubs'', which receive and distribute a large amount of information. Asymptotic learning therefore requires information …

that these two types of externalities co-exist, but differ in their spatial distribution and attenuation within cities …-city industry cluster in a diversified, large city appears to let firms enjoy the benefits of local industry-specific externalities …