The $m$-plane distribution in an $n$-dimensional Riemannian space

The author generalizes some notions (such as canjugate directions, directions of curvature of the first and the second kind, principal directions), well known for $m$-dirnensional surfaces in Euclidean $n$-space to the case of a distribution of m-planes in Riemannian $V_n$. Various related results are obtained, using the method of G. F. Laptev.