∀ {I₁ : Type u_1} {I₂ : Type u_2} {I₁₂ : Type u_4} {c₁ : ComplexShape I₁} {c₂ : ComplexShape I₂}
  {c₁₂ : ComplexShape I₁₂} {inst : TotalComplexShape c₁ c₂ c₁₂} {inst_1 : TotalComplexShape c₂ c₁ c₁₂}
  {inst_2 : TotalComplexShapeSymmetry c₁ c₂ c₁₂} {inst_3 : TotalComplexShapeSymmetry c₂ c₁ c₁₂}
  [self : TotalComplexShapeSymmetrySymmetry c₁ c₂ c₁₂] (i₁ : I₁) (i₂ : I₂), c₂.σ c₁ c₁₂ i₂ i₁ = c₁.σ c₂ c₁₂ i₁ i₂