Module: Mathlib.Topology.Sheaves.LocalPredicate

Goal state before:
pp: case refine_1
X : TopCat
T : ↑X → Type u_1
P : LocalPredicate T
ι : Type u_2
U : ι → Opens ↑X
sf : (i : ι) → ToType ((subpresheafToTypes P.toPrelocalPredicate).obj (op (U i)))
sf_comp : (subpresheafToTypes P.toPrelocalPredicate).IsCompatible U sf
sf' : (i : ι) → (X.presheafToTypes T).obj (op (U i)) := fun i ↦ ↑(sf i)
sf'_comp : (X.presheafToTypes T).IsCompatible U sf'
gl : ToType ((X.sheafToTypes T).obj.obj (op (iSup U)))
gl_spec : IsGluing (X.sheafToTypes T).obj U sf' gl
gl_uniq :
  ∀ (y : ToType ((X.sheafToTypes T).obj.obj (op (iSup U)))),
    (fun s ↦ IsGluing (X.sheafToTypes T).obj U sf' s) y → y = gl
⊢ P.pred gl

pp: case refine_2
X : TopCat
T : ↑X → Type u_1
P : LocalPredicate T
ι : Type u_2
U : ι → Opens ↑X
sf : (i : ι) → ToType ((subpresheafToTypes P.toPrelocalPredicate).obj (op (U i)))
sf_comp : (subpresheafToTypes P.toPrelocalPredicate).IsCompatible U sf
sf' : (i : ι) → (X.presheafToTypes T).obj (op (U i)) := fun i ↦ ↑(sf i)
sf'_comp : (X.presheafToTypes T).IsCompatible U sf'
gl : ToType ((X.sheafToTypes T).obj.obj (op (iSup U)))
gl_spec : IsGluing (X.sheafToTypes T).obj U sf' gl
gl_uniq :
  ∀ (y : ToType ((X.sheafToTypes T).obj.obj (op (iSup U)))),
    (fun s ↦ IsGluing (X.sheafToTypes T).obj U sf' s) y → y = gl
⊢ (fun s ↦ (subpresheafToTypes P.toPrelocalPredicate).IsGluing U sf s) ⟨gl, ?refine_1⟩

pp: case refine_3
X : TopCat
T : ↑X → Type u_1
P : LocalPredicate T
ι : Type u_2
U : ι → Opens ↑X
sf : (i : ι) → ToType ((subpresheafToTypes P.toPrelocalPredicate).obj (op (U i)))
sf_comp : (subpresheafToTypes P.toPrelocalPredicate).IsCompatible U sf
sf' : (i : ι) → (X.presheafToTypes T).obj (op (U i)) := fun i ↦ ↑(sf i)
sf'_comp : (X.presheafToTypes T).IsCompatible U sf'
gl : ToType ((X.sheafToTypes T).obj.obj (op (iSup U)))
gl_spec : IsGluing (X.sheafToTypes T).obj U sf' gl
gl_uniq :
  ∀ (y : ToType ((X.sheafToTypes T).obj.obj (op (iSup U)))),
    (fun s ↦ IsGluing (X.sheafToTypes T).obj U sf' s) y → y = gl
⊢ ∀ (y : ToType ((subpresheafToTypes P.toPrelocalPredicate).obj (op (iSup U)))),
    (fun s ↦ (subpresheafToTypes P.toPrelocalPredicate).IsGluing U sf s) y → y = ⟨gl, ?refine_1⟩

Tactic:
· -- Our first goal is to show that this chosen gluing satisfies the
      -- predicate. Of course, we use locality of the predicate.
      apply P.locality
      rintro ⟨x, mem⟩
      -- Once we're at a particular point `x`, we can select some open set `x ∈ U i`.
      choose i hi using Opens.mem_iSup.mp mem
      -- We claim that the predicate holds in `U i`
      use U i, hi, Opens.leSupr U i
      -- This follows, since our original family `sf` satisfies the predicate
      convert! (sf i).property using 1
      exact gl_spec i

Goal state after:
case refine_2
X : TopCat
T : ↑X → Type u_1
P : LocalPredicate T
ι : Type u_2
U : ι → Opens ↑X
sf : (i : ι) → ToType ((subpresheafToTypes P.toPrelocalPredicate).obj (op (U i)))
sf_comp : (subpresheafToTypes P.toPrelocalPredicate).IsCompatible U sf
sf' : (i : ι) → (X.presheafToTypes T).obj (op (U i)) := fun i ↦ ↑(sf i)
sf'_comp : (X.presheafToTypes T).IsCompatible U sf'
gl : ToType ((X.sheafToTypes T).obj.obj (op (iSup U)))
gl_spec : IsGluing (X.sheafToTypes T).obj U sf' gl
gl_uniq :
  ∀ (y : ToType ((X.sheafToTypes T).obj.obj (op (iSup U)))),
    (fun s ↦ IsGluing (X.sheafToTypes T).obj U sf' s) y → y = gl
⊢ (fun s ↦ (subpresheafToTypes P.toPrelocalPredicate).IsGluing U sf s) ⟨gl, ⋯⟩

case refine_3
X : TopCat
T : ↑X → Type u_1
P : LocalPredicate T
ι : Type u_2
U : ι → Opens ↑X
sf : (i : ι) → ToType ((subpresheafToTypes P.toPrelocalPredicate).obj (op (U i)))
sf_comp : (subpresheafToTypes P.toPrelocalPredicate).IsCompatible U sf
sf' : (i : ι) → (X.presheafToTypes T).obj (op (U i)) := fun i ↦ ↑(sf i)
sf'_comp : (X.presheafToTypes T).IsCompatible U sf'
gl : ToType ((X.sheafToTypes T).obj.obj (op (iSup U)))
gl_spec : IsGluing (X.sheafToTypes T).obj U sf' gl
gl_uniq :
  ∀ (y : ToType ((X.sheafToTypes T).obj.obj (op (iSup U)))),
    (fun s ↦ IsGluing (X.sheafToTypes T).obj U sf' s) y → y = gl
⊢ ∀ (y : ToType ((subpresheafToTypes P.toPrelocalPredicate).obj (op (iSup U)))),
    (fun s ↦ (subpresheafToTypes P.toPrelocalPredicate).IsGluing U sf s) y → y = ⟨gl, ⋯⟩