Independence of Smith-dominated alternatives: Difference between revisions

'''Independence of Smith-dominated alternatives''' (ISDA), also sometimes called '''Smith-IIA''' (Smith-Independence of Irrelevant Alternatives), says that if one option (X) wins an election, and a new alternative (Y) is added, X will still win the election if Y is not in the [[Smith set]]. ISDA implies [[Smith criterion|Smith]] and thus [[Condorcet criterion|Condorcet]], since logically speaking, if an ISDA-passing method's winner were not in the Smith set, eliminating everyone outside of the Smith set would have to change the winner. Some Condorcet methods (e.g. [[Schulze method|Schulze]]) satisfy ISDA.