MathDB
pairwise sums a_i + a_j contains as few different numbers as possible

Source: Polish MO Finals 1968 p4

August 22, 2024
combinatoricsnumber theory

Problem Statement

Given an integer n>2n > 2, give an example of a set of nn mutually different numbers a1,...,ana_1,...,a_n for which the set of their pairwise sums ai+aja_i + a_j (iji \ne j) contains as few different numbers as possible; also give an example of a set of n different numbers b1,...,bnb_1,...,b_n for which the set of their pairwise sums bi+bjb_i+b_j (iji \ne j) contains as many different numbers as possible;