Rationalization of indecisive choice behavior by pluralist ballots

We describe a bounded rationality approach for indecisive choice behavior, in which all, some or none of the items in a menu may be selected. Choice behavior is s-pluralist if there is a population of voters – encoded by arbitrary binary relations – such an item is selected from a menu if and only if it is endorsed by a share of voters larger than s. We prove that all forms of pluralism are equivalent to Axiom alpha. We also examine special forms of pluralism, in which the share of voters is either minimum (liberal) or more than one half (democratic).