We characterize a new quasi-ordering on the collection of opportunity (or choice) sets. This new rule combines two criteria: the individual preferences on the universal set of options and the number of maximal options in the opportunity set. This new rule is compared with the indirect utility...

The existence of a Paretian and finitely anonymous ordering in the set of infinite utility streams implies the existence of a non-Ramsey set (a nonconstructive object whose existence requires the axiom of choice). Therefore, each Paretian and finitely anonymous quasi-ordering either is...