MathDB
Table of Permutations

Source: 2021 ISL C8

July 12, 2022
combinatorics

Problem Statement

Determine the largest integer NN for which there exists a table TT of integers with NN rows and 100100 columns that has the following properties: (i)\text{(i)} Every row contains the numbers 11, 22, \ldots, 100100 in some order. (ii)\text{(ii)} For any two distinct rows rr and ss, there is a column cc such that T(r,c)T(s,c)2|T(r,c) - T(s, c)|\geq 2. (Here T(r,c)T(r,c) is the entry in row rr and column cc.)