This paper examines the interactive effect of distance and trade on international conflict and cooperation. The effect … of geographic distance depends on trade, while the effect of trade varies with geographic distance. Trade reduces …

of natural selection are made weaker because trade allows people to specialize in those activities where they are strong …, and to offset their weaknesses by purchasing adequate goods on the market. Absent trade, people must allocate their time … alleles at all locations. Under trade, there exist long-run equilibria where less fit individuals are able to achieve the same …