Equally spaced collinear points in Euclidean Ramsey theory

Abstract

It is proved that for $k\ge 4$, if the points of $k$-dimensional Euclidean space are coloured in red and blue, then there are either two red points distance one apart or $k+3$ blue collinear points with distance one between any two consecutive points. This result is new for $4\le k\le 10$.