Green points and red segments in a data space (a. k. a. cherries)
Source: 67 Polish MO 2016 Second Round - Problem 6
April 30, 2018
combinatoricsgraph theoryPolandcombinatorics unsolved
Problem Statement
() green points are in a data space and no green points lie on one plane. Some segments which connect green points have been colored red. Number of red segments is even. Each two green points are connected with polyline which is build from red segments. Show that red segments can be split on pairs, such that segments from one pair have common end.