6.241
So lautet der Beweis des Satzes 2 × 2 = 4:
[Nur angedeutet]
ν)μ'x = Ων × μ'x Def.
Ω2 × 2'x = (Ω2)2'x = (Ω2)1 + 1'x = Ω22'x = Ω1 + 11 + 1'x = (Ω'Ω)'(Ω'Ω)'x = Ω'Ω'Ω'Ω'x = Ω1 + 1 + 1 + 1'x = Ω4'x