MathDB

8

Part of 1972 Canada National Olympiad

Problems(1)

Election campaign

Source: 0

6/25/2006
During a certain election campaign, pp different kinds of promises are made by the different political parties (p>0p>0). While several political parties may make the same promise, any two parties have at least one promise in common; no two parties have exactly the same set of promises. Prove that there are no more than 2pāˆ’12^{p-1} parties.