MathDB
p|a_ib_j-a_jb_i

Source: 2022 Thailand Onlline MO P7

April 4, 2022
number theory

Problem Statement

Let pp be a prime number, and let a1,a2,,apa_1, a_2, \dots , a_p and b1,b2,,bpb_1, b_2, \dots , b_p be 2p2p (not necessarily distinct) integers chosen from the set {1,2,,p1}\{1, 2, \dots , p - 1\}. Prove that there exist integers ii and jj such that 1i<jp1 \le i < j \le p and pp divides aibjajbia_ib_j-a_jb_i.