MathDB
number line can be divided into n parts

Source: Netherlands - Dutch NMO 1966 p5

January 31, 2023
combinatoricsalgebrafunction

Problem Statement

The image that maps xx to 1x1 - x is called complement, the image that maps xx to 1x\frac{1}{x} is called invert. Two numbers xx and yy are called related if they can be transferred into each other by means of complementation and/or inversion. A family is a collection of numbers where every two elements are related. Determine the maximum size nn of such a family. Show that the number line can be divided into nn parts, such that each of those nn parts contains exactly one number from each nn-number family.