MathDB
China TST 2010, Problem 2

Source:

August 28, 2010
algebrapolynomialfunctioncomplex numbersalgebra unsolved

Problem Statement

Let A={a1,a2,,a2010}A=\{a_1,a_2,\cdots,a_{2010}\} and B={b1,b2,,b2010}B=\{b_1,b_2,\cdots,b_{2010}\} be two sets of complex numbers. Suppose 1i<j2010(ai+aj)k=1i<j2010(bi+bj)k\sum_{1\leq i<j\leq 2010} (a_i+a_j)^k=\sum_{1\leq i<j\leq 2010}(b_i+b_j)^k holds for every k=1,2,,2010k=1,2,\cdots, 2010. Prove that A=BA=B.