MathDB
2013 Team #7: Children and their Toy orderings

Source:

February 22, 2013

Problem Statement

There are are nn children and nn toys such that each child has a strict preference ordering on the toys. We want to distribute the toys: say a distribution AA dominates a distribution BA B \ne A if in AA, each child receives at least as preferable of a toy as in BB. Prove that if some distribution is not dominated by any other, then at least one child gets his/her favorite toy in that distribution.