9 cities and two airline companies
Source: 2015 Cuba 1.2
September 20, 2024
combinatorics
Problem Statement
In a certain country there are 9 cities and two airline companies: AeroSol and AeroLuna. Between each pair of cities there are flights from one and only one of them. the two companies. Furthermore, for any triple of cities , , σt least one of the flights between them is served by AeroLuna. It is possible to find cities such that all flights between them be served by AeroLuna?