Colour Theory, Linear Algebra, Vector Space, Colorimetry, Linear Transformation.
of the same colour added to two other lights of the same colour produce mixtures that are also the same colour, i.e. if colour A ⇄ colour B and colour C ⇄ colour D, then colour A + colour C ⇄ colour B + colour D, where ⇄ means colour matching. Assuming that the set V has two elements of colour A