Condorcet winner criterionAn electoral system satisfies the Condorcet winner criterion (pronkɒndɔrˈseɪ) if it always chooses the Condorcet winner when one exists. The candidate who wins a majority of the vote in every head-to-head election against each of the other candidates - that is, a candidate preferred by more voters than any others - is the Condorcet winner, although Condorcet winners do not exist in all cases. It is sometimes simply referred to as the "Condorcet criterion", though it is very different from the "Condorcet loser criterion".
Condorcet methodA Condorcet method (pronkɒndɔrˈseɪ; kɔ̃dɔʁsɛ) is an election method that elects the candidate who wins a majority of the vote in every head-to-head election against each of the other candidates, that is, a candidate preferred by more voters than any others, whenever there is such a candidate. A candidate with this property, the pairwise champion or beats-all winner, is formally called the Condorcet winner. The head-to-head elections need not be done separately; a voter's choice within any given pair can be determined from the ranking.
Condorcet paradoxThe Condorcet paradox (also known as the voting paradox or the paradox of voting) in social choice theory is a situation noted by the Marquis de Condorcet in the late 18th century, in which collective preferences can be cyclic, even if the preferences of individual voters are not cyclic. This is paradoxical, because it means that majority wishes can be in conflict with each other: Suppose majorities prefer, for example, candidate A over B, B over C, and yet C over A.
Minimax Condorcet methodIn voting systems, the Minimax Condorcet method (often referred to as "the Minimax method") is one of several Condorcet methods used for tabulating votes and determining a winner when using ranked voting in a single-winner election. It is sometimes referred to as the Simpson–Kramer method, and the successive reversal method. Minimax selects as the winner the candidate whose greatest pairwise defeat is smaller than the greatest pairwise defeat of any other candidate: or, put another way, "the only candidate whose support never drops below [N] percent" in any pairwise contest, with N as high as possible.
Condorcet loser criterionIn single-winner voting system theory, the Condorcet loser criterion (CLC) is a measure for differentiating voting systems. It implies the majority loser criterion but does not imply the Condorcet winner criterion. A voting system complying with the Condorcet loser criterion will never allow a Condorcet loser to win. A Condorcet loser is a candidate who can be defeated in a head-to-head competition against each other candidate.
Centipede gameIn game theory, the centipede game, first introduced by Robert Rosenthal in 1981, is an extensive form game in which two players take turns choosing either to take a slightly larger share of an increasing pot, or to pass the pot to the other player. The payoffs are arranged so that if one passes the pot to one's opponent and the opponent takes the pot on the next round, one receives slightly less than if one had taken the pot on this round, but after an additional switch the potential payoff will be higher.
Instant-runoff votingInstant-runoff voting (IRV) is an electoral system that uses ranked voting. Its purpose is to elect the majority choice in single-member districts in which there are more than two candidates and thus help ensure majority rule. It is a single-winner version of single transferable voting. Formerly the term "instant-runoff voting" was used for what many people now call contingent voting or supplementary vote.
Chicken (game)The game of chicken, also known as the hawk–dove game or snowdrift game, is a model of conflict for two players in game theory. The principle of the game is that while the ideal outcome is for one player to yield (to avoid the worst outcome if neither yields), the individuals try to avoid it out of pride for not wanting to look like a "chicken". Each player taunts the other to increase the risk of shame in yielding. However, when one player yields, the conflict is avoided, and the game is for the most part over.
Cooperative game theoryIn game theory, a cooperative game (or coalitional game) is a game with competition between groups of players ("coalitions") due to the possibility of external enforcement of cooperative behavior (e.g. through contract law). Those are opposed to non-cooperative games in which there is either no possibility to forge alliances or all agreements need to be self-enforcing (e.g. through credible threats). Cooperative games are often analysed through the framework of cooperative game theory, which focuses on predicting which coalitions will form, the joint actions that groups take and the resulting collective payoffs.
Majority ruleMajority rule is the principle that the group that has the most supporters gets its way. A majority is more than half of the voters involved, and rule by such a majority is thought to be to the benefit of more than rule by less than half (a mere minority) would be. Majority rule is the binary decision rule most often used in decision-making bodies, including many legislatures of democratic nations. Where no one party wins a majority of the seats in a legislature, the majority of legislators that wields power is partly composed of members of other parties in support.
Coalition governmentA coalition government is a form of government in which political parties cooperate to form a government. The usual reason for such an arrangement is that no single party has achieved an absolute majority after an election, an atypical outcome in nations with majoritarian electoral systems, but common under proportional representation. A coalition government might also be created in a time of national difficulty or crisis (for example, during wartime or economic crisis) to give a government the high degree of perceived political legitimacy or collective identity, it can also play a role in diminishing internal political strife.
Schulze methodThe Schulze method (ˈʃʊltsə) is an electoral system developed in 1997 by Markus Schulze that selects a single winner using votes that express preferences. The method can also be used to create a sorted list of winners. The Schulze method is also known as Schwartz Sequential dropping (SSD), cloneproof Schwartz sequential dropping (CSSD), the beatpath method, beatpath winner, path voting, and path winner.
Majority criterionThe majority criterion is a single-winner voting system criterion, used to compare such systems. The criterion states that "if one candidate is ranked first by a majority (more than 50%) of voters, then that candidate must win". Some methods that comply with this criterion include any Condorcet method, instant-runoff voting, Bucklin voting, and plurality voting.
Smith criterionThe Smith criterion (sometimes generalized Condorcet criterion, but this can have other meanings) is a voting systems criterion defined such that it's satisfied when a voting system always elects a candidate that is in the Smith set, which is the smallest non-empty subset of the candidates such that every candidate in the subset is majority-preferred over every candidate not in the subset. (A candidate X is said to be majority-preferred over another candidate Y if, in a one-on-one competition between X & Y, the number of voters who prefer X over Y exceeds the number of voters who prefer Y over X.
CoalitionA coalition is formed when two or more people or groups temporarily work together to achieve a common goal. The term is most frequently used to denote a formation of power in political or economic spaces. According to A Guide for Political Parties published by the National Democratic Institute and the Oslo Center for Peace and Human Rights, there are five steps to coalition building. The first step in coalition building involves developing a party strategy that will prepare for successful negotiation.
Plurality votingPlurality voting refers to electoral systems in which a candidate(s), who poll more than any other counterpart (that is, receive a plurality), are elected. In systems based on single-member districts, it elects just one member per district and may also be referred to as first-past-the-post (FPTP), single-member plurality (SMP/SMDP), single-choice voting (an imprecise term as non-plurality voting systems may also use a single choice), simple plurality or relative majority (as opposed to an absolute majority, where more than half of votes is needed, this is called majority voting).
Copeland's methodCopeland's method is a ranked voting method based on a scoring system of pairwise "wins", "losses", and "ties". The method has a long history: Ramon Llull described the system in 1299, so it is sometimes referred to as "Llull's method" The Marquis de Condorcet described a similar system in the 1780s, so the method could be referred to as "Condorcet's method", but instead other systems were subsequently devised that choose the Condorcet winner. Arthur Herbert Copeland described the system in the 1950s, so it has been frequently been called "Copeland's method".
MajorityA majority, also called a simple majority or absolute majority to distinguish it from related terms, is more than half of the total. It is a subset of a set consisting of more than half of the set's elements. For example, if a group consists of 20 individuals, a majority would be 11 or more individuals, while having 10 or fewer individuals would not constitute a majority. "Majority" can be used to specify the voting requirement, as in a "majority vote", which means more than half of the votes cast.
Non-cooperative game theoryA non-cooperative game is a form of game under the topic of game theory. Non-cooperative games are used in situations where there are competition between the players of the game. In this model, there are no external rules that enforces the cooperation of the players therefore it is typically used to model a competitive environment. This is stated in various accounts most prominent being John Nash's paper.
Electronic votingElectronic voting (also known as e-voting) is voting that uses electronic means to either aid or take care of casting and counting ballots. Depending on the particular implementation, e-voting may use standalone electronic voting machines (also called EVM) or computers connected to the Internet (online voting). It may encompass a range of Internet services, from basic transmission of tabulated results to full-function online voting through common connectable household devices.
