Polychromatic Number of the Plane and Results Near the Lower Bound
摘要
When a great problem withstands all assaults, mathematicians create many related problems. It gives them something to solve, plus sometimes there is an extra gain in this process, when an insight into a related problem brings new ways to see and conquer the original one. Numerous problems have been posed around the chromatic number of the plane. I would like to share with you my favorite among them.