  One of the better studied properties for operators in judgment aggregation is
independence, which essentially dictates that the collective judgment on one
issue should not depend on the individual judgments given on some other
issue(s) in the same agenda. Independence, although considered a desirable
property, is too strong, because together with mild additional conditions it
implies dictatorship. We propose here a weakening of independence, named agenda
separability: a judgment aggregation rule satisfies it if, whenever the agenda
is composed of several independent sub-agendas, the resulting collective
judgment sets can be computed separately for each sub-agenda and then put
together. We show that this property is discriminant, in the sense that among
judgment aggregation rules so far studied in the literature, some satisfy it
and some do not. We briefly discuss the implications of agenda separability on
the computation of judgment aggregation rules.
