Documentation

Mathlib.AlgebraicGeometry.AffineSpace

Affine space #

Main definitions #

𝔸(n; S) is the affine n-space over S. Note that n is an arbitrary index type (e.g. Fin m).

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    𝔸(n; S) is the affine n-space over S.

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      The map from the affine n-space over S to the integral model Spec ℤ[n].

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        Morphisms into Spec ℤ[n] are equivalent the choice of n global sections. Use homOverEquiv instead.

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          @[simp]
          theorem AlgebraicGeometry.AffineSpace.toSpecMvPolyIntEquiv_symm_apply (n : Type v) {X : Scheme} (v : n(X.presheaf.obj (Opposite.op ))) :
          def AlgebraicGeometry.AffineSpace.coord {n : Type v} (S : Scheme) (i : n) :
          ((AffineSpace n S).presheaf.obj (Opposite.op ))

          The standard coordinates of 𝔸(n; S).

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            def AlgebraicGeometry.AffineSpace.homOfVector {n : Type v} {S X : Scheme} (f : X S) (v : n(X.presheaf.obj (Opposite.op ))) :

            The morphism X ⟶ 𝔸(n; S) given by a X ⟶ S and a choice of n-coordinate functions.

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              theorem AlgebraicGeometry.AffineSpace.homOfVector_over {n : Type v} {S X : Scheme} (f : X S) (v : n(X.presheaf.obj (Opposite.op ))) :
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              theorem AlgebraicGeometry.AffineSpace.homOfVector_appTop_coord {n : Type v} {S X : Scheme} (f : X S) (v : n(X.presheaf.obj (Opposite.op ))) (i : n) :
              (Scheme.Hom.appTop (homOfVector f v)).hom (coord S i) = v i
              def AlgebraicGeometry.AffineSpace.homOverEquiv {n : Type v} (S : Scheme) {X : Scheme} [X.Over S] :
              { f : X AffineSpace n S // Scheme.Hom.IsOver f S } (n(X.presheaf.obj (Opposite.op )))

              S-morphisms into Spec 𝔸(n; S) are equivalent to the choice of n global sections.

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                @[simp]
                theorem AlgebraicGeometry.AffineSpace.homOverEquiv_apply {n : Type v} (S : Scheme) {X : Scheme} [X.Over S] (f : { f : X AffineSpace n S // Scheme.Hom.IsOver f S }) (i : n) :
                (homOverEquiv S) f i = (Scheme.Hom.appTop f).hom (coord S i)
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                theorem AlgebraicGeometry.AffineSpace.homOverEquiv_symm_apply_coe {n : Type v} (S : Scheme) {X : Scheme} [X.Over S] (v : n(X.presheaf.obj (Opposite.op ))) :
                ((homOverEquiv S).symm v) = homOfVector (X S) v

                The affine space over an affine base is isomorphic to the spectrum of the polynomial ring. Also see AffineSpace.SpecIso.

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                  The affine space over an affine base is isomorphic to the spectrum of the polynomial ring.

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                    𝔸(n; S) is functorial wrt S.

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                      theorem AlgebraicGeometry.AffineSpace.map_appTop_coord {n : Type v} {S T : Scheme} (f : S T) (i : n) :
                      (Scheme.Hom.appTop (map n f)).hom (coord T i) = coord S i
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                      The map between affine spaces over affine bases is isomorphic to the natural map between polynomial rings.

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                        theorem AlgebraicGeometry.AffineSpace.reindex_appTop_coord {n m : Type v} (i : mn) (S : Scheme) (j : m) :
                        (Scheme.Hom.appTop (reindex i S)).hom (coord S j) = coord S (i j)
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                        theorem AlgebraicGeometry.AffineSpace.reindex_comp {n₁ n₂ n₃ : Type v} (i : n₁n₂) (j : n₂n₃) (S : Scheme) :
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                        theorem AlgebraicGeometry.AffineSpace.map_reindex {n₁ n₂ : Type v} (i : n₁n₂) {S T : Scheme} (f : S T) :

                        The affine space as a functor.

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                          theorem AlgebraicGeometry.AffineSpace.functor_obj_map (n : Type vᵒᵖ) {X✝ Y✝ : Scheme} (f : X✝ Y✝) :
                          (functor.obj n).map f = map (Opposite.unop n) f
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                          theorem AlgebraicGeometry.AffineSpace.functor_map_app {n m : Type vᵒᵖ} (i : n m) (S : Scheme) :
                          (functor.map i).app S = reindex i.unop S