MathDB
Strongly majorizing pairs of sequences

Source: St Petersburg 2022 10.2~11.4

September 28, 2022
combinatorics

Problem Statement

We will say that a set of real numbers A=(a1,...,a17)A = (a_1,... , a_{17}) is stronger than the set of real numbers B=(b1,...,b17)B = (b_1, . . . , b_{17}), and write A>BA >B if among all inequalities ai>bja_i > b_j the number of true inequalities is at least 33 times greater than the number of false. Prove that there is no chain of sets A1,A2,...,ANA_1, A_2, . . . , A_N such that A1>A2>AN>A1A_1>A_2> \cdots A_N>A_1.
Remark: For 11.4, the constant 33 is changed to 22 and N=3N=3 and 1717 is changed to mm and nn in the definition (the number of elements don't have to be equal).