Normal numbers of piecewise-linear manifolds

A definition is given of the normal class of the immersion of a closed piecewise-linear manifold in a piecewise-linear manifold. It is shown that this number is zero for the immersion of an orientable manifold in euclidean space of any dimension. A complete investigation is carried out of normal classes of piecewise-smooth immersions of nonorientable manifolds in a euclidean space with dimension twice that of the manifolds.