The current air traffic flow - management system used by the FAA
uses multiple algorithms, or sets of rules, to manage aggregate delays.
As @SJuan76 pointed out, there are
multiple algorithms that deal with representing votes proportionally (that don't require dividing the elected in parts).
All three credit bureaus have
multiple algorithms that produce a score based off the credit profile, depending on who is paying for the score: credit card companies, auto dealers, cell phone providers, mortgage lenders, direct consumers, etc..