MathDB
Romania TST 2022 Day 2 P3

Source: Romania TST 2022

May 15, 2022
inequalitiesalgebraromaniaRomanian TST

Problem Statement

Let n2n\geq 2 be an integer. Let aij, i,j=1,2,,na_{ij}, \ i,j=1,2,\ldots,n be n2n^2 positive real numbers satisfying the following conditions:
[*]For all i=1,,ni=1,\ldots,n we have aii=1a_{ii}=1 and, [*]For all j=2,,nj=2,\ldots,n the numbers aij, i=1,,j1a_{ij}, \ i=1,\ldots, j-1 form a permutation of 1/aji, i=1,,j1.1/a_{ji}, \ i=1,\ldots, j-1.
Given that Si=ai1++ainS_i=a_{i1}+\cdots+a_{in}, determine the maximum value of the sum 1/S1++1/Sn.1/S_1+\cdots+1/S_n.