 A very natural condition has been found by Kraus, Lehmann, and Magidor that corresponds to Rational Monotony: that of ranked models. (No condition on preference structures has been found that ensures disjunctive rationality without also ensuring rational monotony.) A preferential structure \(\mathcal{M}\) satisfies the Ranked Models condition just in case there is a function \(r\) that assigns an ordinal number to each model in such a way that \(M \prec M'\) iff \(r(M) \lt r(M')\). Let’s say that a preferential consequence relation is a rational relation just in case it satisfies Rational Monotony, and that a preferential structure is a rational structure just in case it satisfies the ranked models condition. Kraus, Lehmann, and Magidor (Kraus, Lehmann, and Magidor 1990; Makinson 1994, 71–81) also proved the following representation theorem: