In this short note, we investigate some features of the space I ( R ,R ) of linear injective maps from R d into R; in particular, we discuss in detail its relationship with the Stiefel manifold Vm,d , viewed, in this context, as the set of orthonormal systems of d vectors in R. Finally, we show that the Stiefel manifold Vm,d is a deformation retract of I ( R ,R ) . One possible application of t...