The Condorcet winner is a candidate who would win a head-to-head election against every other candidate. It is not a social choice function because it may not always exist.

Arrow's impossibility theorem states that there is no social choice function that satisfies all of the following properties: unanimity, monotonicity, independence of irrelevant alternatives, and universal domain.

Ranked-choice voting is a system in which voters rank the candidates in order of preference. It is not a type of voting system because it does not use a single ballot to determine the winner.

Libertarianism is a political philosophy that emphasizes individual liberty and minimal government intervention. It is not a type of social welfare function because it does not specify how to distribute resources among individuals.

Matching is a problem in which we want to assign objects to agents in a way that maximizes the total utility. It is not a type of social choice problem because it does not involve choosing a single alternative from a set of alternatives.

The Condorcet method is a method for finding the Condorcet winner. It is not a type of social choice mechanism because it does not specify how to aggregate the preferences of the voters.

Libertarianism is a political philosophy that emphasizes individual liberty and minimal government intervention. It is not a type of social choice theory because it does not provide a framework for making social choices.

The Gibbard-Satterthwaite theorem is a result in social choice theory that states that there is no voting system that is both strategy-proof and non-dictatorial. It is not a type of voting paradox because it does not involve a specific voting system.

The Condorcet winner is a candidate who would win a head-to-head election against every other candidate. It is not a type of social choice rule because it may not always exist.

The Condorcet method is a method for finding the Condorcet winner. It is not a type of social choice aggregation method because it does not specify how to aggregate the preferences of the voters.

The Condorcet winner is a candidate who would win a head-to-head election against every other candidate. It is not a type of social choice function because it may not always exist.

Ranked-choice voting is a system in which voters rank the candidates in order of preference. It is not a type of voting system because it does not use a single ballot to determine the winner.

Libertarianism is a political philosophy that emphasizes individual liberty and minimal government intervention. It is not a type of social welfare function because it does not specify how to distribute resources among individuals.

Matching is a problem in which we want to assign objects to agents in a way that maximizes the total utility. It is not a type of social choice problem because it does not involve choosing a single alternative from a set of alternatives.

The Condorcet method is a method for finding the Condorcet winner. It is not a type of social choice mechanism because it does not specify how to aggregate the preferences of the voters.