A Euclidean Ramsey Result in the Plane

[摘要] An old question in Euclidean Ramsey theory asks, if the points in the plane are red-blue coloured, does there always exist a red pair of points at unit distance or five blue points in line separated by unit distances? An elementary proof answers this ques

[学科分类] 离散数学和组合数学

[关键词] Euclidean Ramsey theory;Plane;Combinatorial Geometry