Practice problem
What Is Proof by Casework, or Exhaustion?
+2 contributors
Contributors
===
There are 3 candidates for President of Utopia. In Utopia everyone votes for a single candidate, behaves strategically, and knows everyone's political preferences. The day before the election, the news publishes an in-depth report: Utopian Presidential Candidates: The People's #1 Choices:
The report goes on to break down the ranking of each candidate to show there are only 3 camps of people in the population, with these preferences:
Within each camp, everyone coordinates to vote the same way. If everyone behaves perfectly strategically to ensure that the best candidate wins the election, who will be elected President of Utopia?