English
The top affine subspace is affinely equivalent to the ambient space; this is the canonical affine correspondence between the two spaces.
Русский
Проверка: верхнее аффинное подпространство имеет аффинное соответствие с окружающим пространством.
LaTeX
$$$ topEquiv : (\\\\top : AffineSubspace k P) \\\\simeq_a_k P $$$
Lean4
/-- The top affine subspace is linearly equivalent to the affine space.
This is the affine version of `Submodule.topEquiv`. -/
@[simps! linear apply symm_apply_coe]
def topEquiv : (⊤ : AffineSubspace k P) ≃ᵃ[k] P
where
toEquiv := Equiv.Set.univ P
linear := .ofEq _ _ (direction_top _ _ _) ≪≫ₗ Submodule.topEquiv
map_vadd' _ _ := rfl