theorem Th4: :: GEOMTRAP:4

for V being RealLinearSpace
for u, u1, v, v1, w, y being VECTOR of V
for p, q, p1, q1 being Element of the carrier of (AMSpace (V,w,y)) st p = u & q = v & p1 = u1 & q1 = v1 holds
( p,q // p1,q1 iff u,v '||' u1,v1 )