 A pair-negatable agenda: \(X\) has a minimal inconsistent subset \(Y\) that can be rendered consistent by negating a pair of propositions in it. (Equivalently, \(X\) is not isomorphic to a set of propositions whose only connectives are \(\neg\) and \(\leftrightarrow\) in standard propositional logic; see Dokow and Holzman 2010a.)