Про виборчі системи

[bytebuster]

Відповідав тут на запитання:
Q: Does Arrow's Theorem invalidate an alternate voting system?

Imagine this voting algorithm: Each voter ranks their choices. Then, the 1st choice votes are tallied, and the one with the lowest score removed from the running. Those who have the removed contender have their rankings shifted up one, i.e. their second choice is now considered their first choice. Everybody else keeps their rankings.

How does Arrow's Theorem invalidate this? It seems to satisfy all four conditions, but the theorem shows it can't. Which condition does this not meet, and why?

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A: The voting system you describe is called Single transferrable vote (STV).

Arrow's theorem does not discuss STV specifically. Instead, it states that no electoral system exist that satisfies a certain number of criteria at once.

One of these criteria is monotonicity, and there are studies that conclude STV is non-monotonic.

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І тут у коментарях підкинули ахуєнчік. Інтерактивна гра, яка показує результати голосування за різними виборчими системами.
Корочє, я кілька годин грався. Не клікайте, «єслі вам дороґ ваш рассудок і дажє жізнь, дєржитєсь подальше від торфяних болот». ©
Я попередив. :)