The possibility of judgment aggregation for network agendas

Within social choice theory, the new field of judgment aggregation aims at reaching collective judgments on a set of logically interconnected propositions. I investigate decision problems, in which the agenda is a network, composed of atomic propositions and connection rules between them. Networks can represent various realistic decision problems, including most concrete examples given in the literature. Nevertheless, networks are unexplored so far due to problems when modelling connection rules in standard propositional logic. By extending the logic, I prove that, for any network, decision rules satisfying the common conditions always exist, in contrast to the literature's emphasis on impossibilities. I also characterise the class of such decision rules, and propose a simple way to select a decision rule.