Arrow's theorem says that a rank-order voting system with at least three alternatives cannot simultaneously satisfy unrestricted preferences, unanimity, independence of irrelevant alternatives, and absence of a dictator.
The Condorcet paradox is a cycle in collective pairwise preferences even though each individual voter's preference is transitive.
Articles by others on the same topic
Arrow's impossibility theorem, formulated by economist Kenneth Arrow in his 1951 work "Social Choice and Individual Values," addresses the challenges of aggregating individual preferences into a collective decision or social welfare function. The theorem states that no voting system can convert individual preferences into a collective outcome that satisfies a specific set of reasonable criteria at the same time.