The zero module sheaf has finite presentation #
On an arbitrary ringed site with binary products, the zero sheaf of modules admits the empty finite presentation. Thus finite presentation contains a zero object independently of any scheme or coherent-sheaf specialization.
Main result #
instance
SheafOfModules.isFinitePresentation_containsZero
{C : Type u}
[CategoryTheory.Category.{u, u} C]
{J : CategoryTheory.GrothendieckTopology C}
{R : CategoryTheory.Sheaf J RingCat}
[CategoryTheory.HasSheafify J AddCommGrpCat]
[J.WEqualsLocallyBijective AddCommGrpCat]
[∀ (X : C), CategoryTheory.HasSheafify (J.over X) AddCommGrpCat]
[∀ (X : C), (J.over X).WEqualsLocallyBijective AddCommGrpCat]
[CategoryTheory.Limits.HasBinaryProducts C]
:
The zero sheaf of modules has finite presentation.