This is a textbook introducing selected topics in formal social choice theory. Social choice theory studies group choices that are based on information about preferences of members of the group (voting rules being one important special case). This involves economics, which provides the method of...

We allow departures from IIA in Arrow’s framework. Our measure of the extent of a departure is the amount of information needed to socially order a pair of alternatives. We also propose a measure of the scope of an individual’s power. The scope of at least one individual’s power increases...