Module

Scheme_Modules_Hom_epi_iff_locallySurjective.lean

Nyll.AlgebraicCurves.Geometry.Sheaves.Scheme_Modules_Hom_epi_iff_locallySurjective
2 declarations indexed from sourceView source ↗

Epimorphisms and locally surjective module maps

A morphism of module sheaves is an epimorphism precisely when sections locally lift through its components.

Declarations

AlgebraicCurves.Geometry.Sheaves.Proofs.Scheme_Modules_Hom_epi_iff_locallySurjective.SheafOfModules.epi_toSheaf_map_of_epi
Source context 13 commands

Surrounding namespaces, section variables, and local commands at this declaration.

section ProofImplementation
namespace AlgebraicCurves.Geometry.Sheaves.Proofs.Scheme_Modules_Hom_epi_iff_locallySurjective
universe u
open _root_.CategoryTheory
open _root_.CategoryTheory.Limits
open _root_.AlgebraicGeometry
open _root_.Opposite
open _root_.TopologicalSpace
universe v v' u'
namespace SheafOfModules
open _root_.SheafOfModules
open _root_.SheafOfModules
variable {C : Type u'} [Category.{v'} C] {J : GrothendieckTopology C} {R : Sheaf J RingCat.{u}}
  [HasSheafify J AddCommGrpCat.{v}] [J.WEqualsLocallyBijective AddCommGrpCat.{v}]
theorem epi_toSheaf_map_of_epi {M N : SheafOfModules.{v} R} (φ : M ⟶ N) [Epi φ] :
    Epi ((toSheaf R).map φ)
AlgebraicGeometry.Scheme.Modules.Hom.epi_iff_locallySurjective
Source context 19 commands

Surrounding namespaces, section variables, and local commands at this declaration.

section ProofImplementation
namespace AlgebraicCurves.Geometry.Sheaves.Proofs.Scheme_Modules_Hom_epi_iff_locallySurjective
universe u
open _root_.CategoryTheory
open _root_.CategoryTheory.Limits
open _root_.AlgebraicGeometry
open _root_.Opposite
open _root_.TopologicalSpace
universe v v' u'
namespace AlgebraicGeometry
open _root_.AlgebraicGeometry
namespace Scheme
open _root_.AlgebraicGeometry.Scheme
namespace Modules
open _root_.AlgebraicGeometry.Scheme.Modules
open _root_.AlgebraicGeometry.Scheme.Modules
open _root_.AlgebraicGeometry.Scheme
open _root_.AlgebraicGeometry
variable {X : Scheme.{u}}
theorem _root_.AlgebraicGeometry.Scheme.Modules.Hom.epi_iff_locallySurjective {M N : X.Modules} (φ :
  M ⟶ N) :
    Epi φ ↔ ∀ (U : X.Opens) (s : Γ(N, U)), ∀ x ∈ U, ∃ (V : X.Opens) (i : V ≤ U),
      x ∈ V ∧ N.presheaf.map (homOfLE i).op s ∈ Set.range (φ.app V)