Equations: Summary 6

    Lines l in 3-space correspond to points

in Plücker space satisfying the quadratic Plücker equation
  =   0.

    In this formulation, the equation for a general line l to meet the fixed line m is linear

  =   0
and the equation to be tangent to a sphere is quadratic
  =   0,
where Q is the quadratic form defining the sphere.