∀ {A : Type u_1} {G : Type u_2} {V : Type u_3} {W : Type u_4} [inst : CommRing A] [inst_1 : Monoid G]
  [inst_2 : AddCommMonoid V] [inst_3 : AddCommMonoid W] [inst_4 : Module A V] [inst_5 : Module A W]
  {ρ : Representation A G V} {σ : Representation A G W} [inst_6 : SizeOf A] [inst_7 : SizeOf G] [inst_8 : SizeOf V]
  [inst_9 : SizeOf W] (toLinearMap : V →ₗ[A] W)
  (isIntertwining' : ∀ (g : G) (v : V), toLinearMap.toFun ((ρ g) v) = (σ g) (toLinearMap.toFun v)),
  sizeOf { toLinearMap := toLinearMap, isIntertwining' := isIntertwining' } = 1 + sizeOf toLinearMap