  Any community in which membership is optional may eventually break apart, or
fork. For example, forks may occur in political parties, business partnerships,
social groups, cryptocurrencies, and federated governing bodies. Forking is
typically the product of informal social processes or the organized action of
an aggrieved minority, and it is not always amicable. Forks usually come at a
cost, and can be seen as consequences of collective decisions that destabilize
the community. Here, we provide a social choice setting in which agents can
report preferences not only over a set of alternatives, but also over the
possible forks that may occur in the face of disagreement. We study this social
choice setting, concentrating on stability issues and concerns of strategic
agent behavior.
