MathDB
2008 KMO P4

Source:

August 9, 2015
combinatoricsnumber theory

Problem Statement

We define A,B,CA, B, C as a partition of N\mathbb{N} if A,B,CA,B,C satisfies the following. (i) A,B,CϕA, B, C \not= \phi (ii) AB=BC=CA=ϕA \cap B = B \cap C = C \cap A = \phi (iii) ABC=NA \cup B \cup C = \mathbb{N}.
Prove that the partition of N\mathbb{N} satisfying the following does not exist. (i) \forall aA,bBa \in A, b \in B, we have a+b+2008Ca+b+2008 \in C (ii) \forall bB,cCb \in B, c \in C, we have b+c+2008Ab+c+2008 \in A (iii) \forall cC,aAc \in C, a \in A, we have c+a+2008Bc+a+2008 \in B