This note is a part of my Zettelkasten. What is below might not be complete or accurate. It is also likely to change often.
30th July, 2020

Arrow's Impossiblity Theorem

Arrow's Impossibility Theorem states that using a Ranked Voting System it is impossible to convert individual prefereces to societal preference such that it meets the following parameters:

  • Non-dictatorship: Preferences of the individual shouldn't become the preference of the group without considering the preference of others.
  • Individual Sovereignity: Individuals should have the freedom to to order the choices in any way
  • Unanimity: If an individual prefers one item to another, the group should do the same.
  • Freedom from irregular alternatives: If one of the choices is removed, the order should remain the same.
  • Deterministism: Presented with the same input individual preference, the societal preference should be deterministic.