The faces of the unit balls of c-norms and c-spectral norms Original Research Article

We give a complete description of the faces of the closed unit ball of an arbitrary c-norm on imagen, and we determine the barycenter, the volume, and the symmetries of each face. As a consequence of a previous result we characterize the faces of the closed unit ball of the corresponding c-spectral norm on the space of n × m real (or complex) matrices.