Some special surfaces in the pseudo-Galilean space
A Pseudo-Galilean space \(G^1_3\) is a three-dimensional space with an absolute figure \(\{\omega,f,I\}\), where \(f\) is a line in the plane of infinity \(\omega\) and \(I\) a hyperbolic involution on \(f\). \(G^1_3\) is metrized by the projective automorphisme group of \(\{\omega,f,I\}\). In the excellently written paper the authors describe some special surfaces in \(G^1_3\) such as helical surfaces, ruled screw surfaces, surfaces of revolution and in particular tori of revolution. As a very nice result they show: Surfaces of revolution \(S_i\) in \(G^1_3\) are flat \((K\equiv 0)\) if and only if they are minimal \((H\equiv 0)\). The paper is completed by 10 interesting figures.
scientific article; zbMATH DE number 5355880