placing lightbulbs around n-gon to light it up
Source: Bulgaria 1986 P4
June 15, 2021
geometrycombinatoricscombinatorial geometry
Problem Statement
Find the smallest integer for which there exists an -gon and a point within it such that, if a light bulb is placed at that point, on each side of the polygon there will be a point that is not lightened. Show that for this smallest value of there always exist two points within the -gon such that the bulbs placed at these points will lighten up the whole perimeter of the -gon.