∀ {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] {i₁ i₁' : I₁},
  c₁.Rel i₁ i₁' → ∀ (i₂ : I₂), c₁.σ c₂ c₁₂ i₁ i₂ * c₁.ε₁ c₂ c₁₂ (i₁, i₂) = c₂.ε₂ c₁ c₁₂ (i₂, i₁) * c₁.σ c₂ c₁₂ i₁' i₂