摘要：Most contributions in axiomatic bargaining are phrased in the space of utilities.
This comes in sharp contrast with standards in most other fields of economic theory.
The present paper shows how Nash’s original axiomatic system can be rephrased
in a natural class of economic environments with lotteries, and how his uniqueness
result can be recovered, provided one completes the system with a property of in-
dependence with respect to preferences over unfeasible alternatives. Similar results
can be derived for the Kalai-Smorodinsky solution if and only if bargaining may
involve multiple goods. The paper also introduces a distinction between welfarism
and cardinal welfarism, and emphasizes that the Nash solution is ordinally invari-
ant on the class of von Neumann-Morgensterm preferences.
