for x, y, z being object
for V being non trivial RealLinearSpace st [x,y,z] in the Collinearity of (ProjectiveSpace V) holds
ex p, q, r being Element of V st
( x = Dir p & y = Dir q & z = Dir r & not p is zero & not q is zero & not r is zero & p,q,r are_LinDep ) by Def6;