The classification of projectively homogeneous surfaces. II (Q1392655)

A submanifold \(M\) in a real projective space is called projectively homogeneous if for any \(p,q\in M\) there exists a projective transformation \(A\) which takes \(p\) to \(q\) and keeps \(M\) invariant. In this paper, the authors give a complete classification of projectively homogeneous surfaces in 3-dimensional real projective space \(P^3\) which are either ruled or degenerate. There are 17 types of such surfaces up to projective transformations in \(P^3\). This work complements the classification of non-ruled and nondegenerate projectively homogeneous surfaces in \(P^3\) given by \textit{K. Nomizu} and \textit{T. Sasaki} [Result. Math. 20, 698-724 (1991; Zbl 0761.53009)] and thus appears as Part II of this paper.