MMO 283 Moscow MO 1954 1001 free endpoints, 5 segments
Source:
August 13, 2019
combinatorial geometrycombinatoricsgraph
Problem Statement
Consider five segments . From each point there can exit either segments or no segments at all, so that the endpoints of any two segments of the resulting graph (system of segments) do not coincide. Can the number of free endpoints of the segments thus constructed be equal to ? (A free endpoint is an endpoint from which no segment begins.)