We assume that in a linear space (P , L) there is a non-empty set M of points with the property that every plane containing a point of M is a projective plane. In section 3 an example is given that in general (P , L) is not a projective space. But if M can be completed by two points to a generating set of P , then (P , L) is a projective space. (1991): 51A05, 51D99, 51E15.
Mathematics Subject Classification