Epimorphisms of light condensed objects #
This file characterises epimorphisms in light condensed sets and modules as the locally surjective morphisms. Here, the condition of locally surjective is phrased in terms of continuous surjections of light profinite sets.
theorem
LightCondensed.isLocallySurjective_iff_locallySurjective_on_lightProfinite
(A : Type u')
[CategoryTheory.Category.{v', u'} A]
[CategoryTheory.ConcreteCategory A]
[CategoryTheory.Limits.PreservesFiniteProducts (CategoryTheory.forget A)]
{X : LightCondensed A}
{Y : LightCondensed A}
(f : X ⟶ Y)
:
CategoryTheory.Sheaf.IsLocallySurjective f ↔ ∀ (S : LightProfinite) (y : (CategoryTheory.forget A).obj (Y.val.obj (Opposite.op S))),
∃ (S' : LightProfinite) (φ : S' ⟶ S) (_ : Function.Surjective ⇑φ) (x :
(CategoryTheory.forget A).obj (X.val.obj (Opposite.op S'))),
(f.val.app (Opposite.op S')) x = (Y.val.map (Opposite.op φ)) y
theorem
LightCondSet.epi_iff_locallySurjective_on_lightProfinite
{X : LightCondSet}
{Y : LightCondSet}
(f : X ⟶ Y)
:
CategoryTheory.Epi f ↔ ∀ (S : LightProfinite) (y : Y.val.obj (Opposite.op S)),
∃ (S' : LightProfinite) (φ : S' ⟶ S) (_ : Function.Surjective ⇑φ) (x : X.val.obj (Opposite.op S')),
f.val.app (Opposite.op S') x = Y.val.map (Opposite.op φ) y
theorem
LightCondMod.epi_iff_locallySurjective_on_lightProfinite
(R : Type u)
[Ring R]
{X : LightCondMod R}
{Y : LightCondMod R}
(f : X ⟶ Y)
:
CategoryTheory.Epi f ↔ ∀ (S : LightProfinite) (y : ↑(Y.val.obj (Opposite.op S))),
∃ (S' : LightProfinite) (φ : S' ⟶ S) (_ : Function.Surjective ⇑φ) (x : ↑(X.val.obj (Opposite.op S'))),
(f.val.app (Opposite.op S')) x = (Y.val.map (Opposite.op φ)) y