On a projective representation of chain geometries

We define a distance d on the set of r-spaces of an n-space. By the transfer of d to the GraßmannianG=G(n, r) we obtain a distinguished class of normal rational curves of order 1, the 1-distance lines, 1=1,..., r, which are in 1–1-correspondence to the so-called generalized reguli of type (r, 1).To every chain geometry there are subspaces T and Z of the surrounding space ofG, such that forV=GT andW = VZ we have a projective representation of on V\W as pointset, where the chains of are exactly the r-distance lines on V\W.Dedicated to Prof.A. Barlotti on occasion of his 60 birthday