2003 integers from 1 to 2003 on blackboard
Source: Argentina 2003 OMA L3 p2
May 12, 2024
combinatoricsnumber theoryalgebra
Problem Statement
On the blackboard are written the integers from to . Lucas must delete numbers. Next, Mauro must choose from the numbers that remain written. If the numbers Mauro chooses form an arithmetic progression, Mauro wins. If not, Lucas wins. Decide if Lucas can choose the numbers he erases so that victory is assured.