olymmath

CIIM 2013 Problem 3

  • Day 1

Given a set of boys and girls, we call a pair (A,B)(A,B) amicable if AA and BB are friends. The friendship relation is symmetric. A set of people is affectionate if it satisfy the following conditions:

i) The set has the same number of boys and girls.

ii) For every four different people A,B,C,DA,B,C,D if the pairs (A,B),(B,C),(C,D)(A,B),(B,C),(C,D) and (D,A)(D,A) are all amicable, then at least one of the pairs (A,C)(A,C) and (B,D)(B,D) is also amicable. iii) At least 12013\frac{1}{2013} of all boy-girl pairs are amicable.

Let mm be a positive integer. Prove that there exists an integer N(m)N(m) such that if a affectionate set has al least N(m)N(m) people, then there exists mm boys that are pairwise friends or mm girls that are pairwise friends.

Dataset text AI-MO AoPS. Quoted with source.

Solutions

No solution is on olymmath yet. Official and human solutions come first when they arrive. AI solutions come after them, with a label.

Add a solution

Similar problems

These problems have the most words in common with this statement.

Locator ciim/2013/p3 · Tag NAH4TW66QJ · Edit this page on GitHub · Keys: j next, k previous