MathDB
Putnam 1954 A1

Source: Putnam 1954

July 17, 2022
Putnamlinear algebramatrixpermutation

Problem Statement

Let nn be an odd integer greater than 1.1. Let AA be an n×nn\times n symmetric matrix such that each row and column consists of some permutation of the integers 1,2,,n.1,2, \ldots, n. Show that each of the integers 1,2,,n1,2, \ldots, n must appear in the main diagonal of AA.