We provide characterizations of four new rules for individual decision-making under complete uncertainty. They are what we call the min-max rule, the max-min rule, the lexicographic min-max rule and the lexicographic max-min rule. These rules provide orderings of the sets of possible outcomes...

In a world admitting a fixed finite set of alternatives, an opinion is an orderedpair of alternatives. Such a pair expresses the idea that one alternative is superior toanother in some sense, and an opinion aggregator assigns a social relation on the set ofalternatives to every possible multiset...