Cupid's Arrow...

In voting theory, one of the most important results is the so called "Arrow's Impossibility Theorem". For the uninitiated, here is the trick to memorize what the theorem is all about.

The theorem states that if a voting system satisfies:
Complete and transitive social preferences;
Universal domain, i.e., any individual preference ordering is allowed;
Pareto efficiency (or unanimity); and
Independence of irrelevant alternatives (IIA);

then there must exist a

Dictator. Well, don't forget that the theorem gots its own name, that is, ARROW's impossibility theorem.

So, just remember: Cupid's Arrow!!

HT to Uncle Marcus.