We use the universe of USPTO data on patents and inventors from 1976 to 2019 to look at the dynamics of coauthorship on patents and its relationship with competition. First, we find an inverted-U relationship between competition and the growth in coauthorship: the number of new collaborators on...

We investigate the complementarity between informal communities and formal government enforcement of norms of reciprocation and exchange. We introduce a model in which people exchange informally within their community as well as externally on a market. We show that informal community and formal...

We investigate the role of networks of military alliances in preventing or encouraging wars between groups of countries. A country is vulnerable to attack if there is some fully-allied group of countries that can defeat that country and its (remaining) allies based on a function of their...

We investigate the role of networks of alliances in preventing (multilateral) interstate wars. We first show that, in the absence of international trade, no network of alliances is peaceful and stable. We then show that international trade induces peaceful and stable networks: trade increases...

Regional quarantine policies, in which a portion of a population surrounding infections are locked down, are an important tool to contain disease. However, jurisdictional governments - such as cities, counties, states, and countries - act with minimal coordination across borders. We show that a...