English
The congruence of identity maps on M and N is the identity on the tensor product: congr Refl(R,M) Refl(R,N) = Refl(R, TensorProduct R M N).
Русский
Сопоставление тождества на M и на N даёт тождественное отображение на произведение: congr_refl_refl = refl на TensorProduct.
LaTeX
$$$ congr\\ (\\mathrm{refl}\\ R\\ M)\\ (\\mathrm{refl}\\ R\\ N) = \\mathrm{refl}\\ R\\ (TensorProduct\\ R\\ M\\ N) $$$
Lean4
@[simp]
theorem congr_refl_refl : congr (.refl R M) (.refl R N) = .refl R _ :=
LinearEquiv.toLinearMap_injective <| ext' fun _ _ ↦ rfl