Module

SubmoduleEmbeddedIso.lean

Nyll.SchemeTheory.Modules.SubmoduleEmbeddedIso
2 declarations indexed from sourceView source ↗

Literal equality from embedded submodule comparisons

An actual morphism commuting with the native inclusions gives pointwise containment. An actual isomorphism commuting with the inclusions therefore gives equality of the original native submodules. In particular, the embedded restriction comparison in the quasicoherent extension theorem can be used by submodule gluing without an assumed section comparison.

Declarations

SheafOfModules.Submodule.le_of_hom_ι

A map of actual submodules commuting with their inclusions gives containment.

Source context 5 commands

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

noncomputable section
universe v v₁ u₁ u
open CategoryTheory
namespace SheafOfModules.Submodule
variable {C : Type u₁} [Category.{v₁} C] {J : GrothendieckTopology C}
  {R : Sheaf J RingCat.{u}} {M : SheafOfModules.{v} R}
theorem le_of_hom_ι (N P : M.Submodule)
    (f : N.toSheafOfModules ⟶ P.toSheafOfModules) (hf : f ≫ P.ι = N.ι) :
    N ≤ P
SheafOfModules.Submodule.eq_of_iso_ι

An isomorphism of submodules respecting their native embeddings gives equality of the actual submodules, including every section submodule.

Source context 5 commands

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

noncomputable section
universe v v₁ u₁ u
open CategoryTheory
namespace SheafOfModules.Submodule
variable {C : Type u₁} [Category.{v₁} C] {J : GrothendieckTopology C}
  {R : Sheaf J RingCat.{u}} {M : SheafOfModules.{v} R}
theorem eq_of_iso_ι (N P : M.Submodule)
    (e : N.toSheafOfModules ≅ P.toSheafOfModules) (he : e.hom ≫ P.ι = N.ι) :
    N = P