Rays from rational points aren't parallel
Source: Kvant Magazine No. 5-6 2024 M2795
August 25, 2024
number theorycombinatorial geometry
Problem Statement
Is it possible to release a ray on a plane from each point with rational coordinates so that no two rays have a common point and at the same time, among the lines containing these rays, no two are parallel and do not coincide?
Proposed by P. Kozhevnikov