Usted buscó: unit vector tangent (Inglés - Griego)

unit vector
μοναδιαίο διάνυσμα

if "r" and "p" in the above flat torus form a unit vector = then "u", "v", and "η" can be used to parameterize the unit 3-sphere in a parameterization associated with the hopf map.
if "r" and "p" in the above flat torus form a unit vector = then "u", "v", and "η" can be used to parameterize the unit 3-sphere in a parameterization associated with the hopf map.