Module: Mathlib.Analysis.Convex.Visible

Goal state before:
pp: case inr.refine_1.refine_1
𝕜 : Type u_1
V : Type u_2
inst✝⁴ : Field 𝕜
inst✝³ : LinearOrder 𝕜
inst✝² : IsStrictOrderedRing 𝕜
inst✝¹ : AddCommGroup V
inst✝ : Module 𝕜 V
s : Set V
x : V
ι : Type u_4
t : Finset ι
a : ι → V
w : ι → 𝕜
hw₀ : ∀ i ∈ t, 0 ≤ w i
hw₁ : ∑ i ∈ t, w i = 1
ha : ∀ i ∈ t, a i ∈ s
hx : x ∉ (convexHull 𝕜) s
hw : IsVisible 𝕜 ((convexHull 𝕜) s) x (∑ i ∈ t, w i • a i)
i : ι
hi : i ∈ t
hwi✝¹ : 0 < w i
hwi✝ : w i < 1
ε : 𝕜
hε : (lineMap x (a i)) ε ∈ (convexHull 𝕜) s
h : (lineMap x (a i)) ε ≠ x ∧ (lineMap x (a i)) ε ≠ a i
hε₀ : 0 < ε
hε₁ : ε < 1
this✝ : 0 < 1 - ε
hwi : 0 < 1 - w i
this :
  Wbtw 𝕜 ((lineMap x (a i)) ε) ((lineMap x (∑ j ∈ t, w j • a j)) ((w i)⁻¹ / ((1 - ε) / ε + (w i)⁻¹)))
    (∑ j ∈ t.erase i, (w j / (1 - w i)) • a j)
⊢ ∀ i_1 ∈ t.erase i, 0 ≤ w i_1 / (1 - w i)

pp: case inr.refine_1.refine_2
𝕜 : Type u_1
V : Type u_2
inst✝⁴ : Field 𝕜
inst✝³ : LinearOrder 𝕜
inst✝² : IsStrictOrderedRing 𝕜
inst✝¹ : AddCommGroup V
inst✝ : Module 𝕜 V
s : Set V
x : V
ι : Type u_4
t : Finset ι
a : ι → V
w : ι → 𝕜
hw₀ : ∀ i ∈ t, 0 ≤ w i
hw₁ : ∑ i ∈ t, w i = 1
ha : ∀ i ∈ t, a i ∈ s
hx : x ∉ (convexHull 𝕜) s
hw : IsVisible 𝕜 ((convexHull 𝕜) s) x (∑ i ∈ t, w i • a i)
i : ι
hi : i ∈ t
hwi✝¹ : 0 < w i
hwi✝ : w i < 1
ε : 𝕜
hε : (lineMap x (a i)) ε ∈ (convexHull 𝕜) s
h : (lineMap x (a i)) ε ≠ x ∧ (lineMap x (a i)) ε ≠ a i
hε₀ : 0 < ε
hε₁ : ε < 1
this✝ : 0 < 1 - ε
hwi : 0 < 1 - w i
this :
  Wbtw 𝕜 ((lineMap x (a i)) ε) ((lineMap x (∑ j ∈ t, w j • a j)) ((w i)⁻¹ / ((1 - ε) / ε + (w i)⁻¹)))
    (∑ j ∈ t.erase i, (w j / (1 - w i)) • a j)
⊢ ∑ i_1 ∈ t.erase i, w i_1 / (1 - w i) = 1

pp: case inr.refine_1.refine_3
𝕜 : Type u_1
V : Type u_2
inst✝⁴ : Field 𝕜
inst✝³ : LinearOrder 𝕜
inst✝² : IsStrictOrderedRing 𝕜
inst✝¹ : AddCommGroup V
inst✝ : Module 𝕜 V
s : Set V
x : V
ι : Type u_4
t : Finset ι
a : ι → V
w : ι → 𝕜
hw₀ : ∀ i ∈ t, 0 ≤ w i
hw₁ : ∑ i ∈ t, w i = 1
ha : ∀ i ∈ t, a i ∈ s
hx : x ∉ (convexHull 𝕜) s
hw : IsVisible 𝕜 ((convexHull 𝕜) s) x (∑ i ∈ t, w i • a i)
i : ι
hi : i ∈ t
hwi✝¹ : 0 < w i
hwi✝ : w i < 1
ε : 𝕜
hε : (lineMap x (a i)) ε ∈ (convexHull 𝕜) s
h : (lineMap x (a i)) ε ≠ x ∧ (lineMap x (a i)) ε ≠ a i
hε₀ : 0 < ε
hε₁ : ε < 1
this✝ : 0 < 1 - ε
hwi : 0 < 1 - w i
this :
  Wbtw 𝕜 ((lineMap x (a i)) ε) ((lineMap x (∑ j ∈ t, w j • a j)) ((w i)⁻¹ / ((1 - ε) / ε + (w i)⁻¹)))
    (∑ j ∈ t.erase i, (w j / (1 - w i)) • a j)
⊢ ∀ i_1 ∈ t.erase i, a i_1 ∈ (convexHull 𝕜) s

Tactic:
· intro j hj
      positivity [hw₀ j <| erase_subset _ _ hj]

Goal state after:
case inr.refine_1.refine_2
𝕜 : Type u_1
V : Type u_2
inst✝⁴ : Field 𝕜
inst✝³ : LinearOrder 𝕜
inst✝² : IsStrictOrderedRing 𝕜
inst✝¹ : AddCommGroup V
inst✝ : Module 𝕜 V
s : Set V
x : V
ι : Type u_4
t : Finset ι
a : ι → V
w : ι → 𝕜
hw₀ : ∀ i ∈ t, 0 ≤ w i
hw₁ : ∑ i ∈ t, w i = 1
ha : ∀ i ∈ t, a i ∈ s
hx : x ∉ (convexHull 𝕜) s
hw : IsVisible 𝕜 ((convexHull 𝕜) s) x (∑ i ∈ t, w i • a i)
i : ι
hi : i ∈ t
hwi✝¹ : 0 < w i
hwi✝ : w i < 1
ε : 𝕜
hε : (lineMap x (a i)) ε ∈ (convexHull 𝕜) s
h : (lineMap x (a i)) ε ≠ x ∧ (lineMap x (a i)) ε ≠ a i
hε₀ : 0 < ε
hε₁ : ε < 1
this✝ : 0 < 1 - ε
hwi : 0 < 1 - w i
this :
  Wbtw 𝕜 ((lineMap x (a i)) ε) ((lineMap x (∑ j ∈ t, w j • a j)) ((w i)⁻¹ / ((1 - ε) / ε + (w i)⁻¹)))
    (∑ j ∈ t.erase i, (w j / (1 - w i)) • a j)
⊢ ∑ i_1 ∈ t.erase i, w i_1 / (1 - w i) = 1

case inr.refine_1.refine_3
𝕜 : Type u_1
V : Type u_2
inst✝⁴ : Field 𝕜
inst✝³ : LinearOrder 𝕜
inst✝² : IsStrictOrderedRing 𝕜
inst✝¹ : AddCommGroup V
inst✝ : Module 𝕜 V
s : Set V
x : V
ι : Type u_4
t : Finset ι
a : ι → V
w : ι → 𝕜
hw₀ : ∀ i ∈ t, 0 ≤ w i
hw₁ : ∑ i ∈ t, w i = 1
ha : ∀ i ∈ t, a i ∈ s
hx : x ∉ (convexHull 𝕜) s
hw : IsVisible 𝕜 ((convexHull 𝕜) s) x (∑ i ∈ t, w i • a i)
i : ι
hi : i ∈ t
hwi✝¹ : 0 < w i
hwi✝ : w i < 1
ε : 𝕜
hε : (lineMap x (a i)) ε ∈ (convexHull 𝕜) s
h : (lineMap x (a i)) ε ≠ x ∧ (lineMap x (a i)) ε ≠ a i
hε₀ : 0 < ε
hε₁ : ε < 1
this✝ : 0 < 1 - ε
hwi : 0 < 1 - w i
this :
  Wbtw 𝕜 ((lineMap x (a i)) ε) ((lineMap x (∑ j ∈ t, w j • a j)) ((w i)⁻¹ / ((1 - ε) / ε + (w i)⁻¹)))
    (∑ j ∈ t.erase i, (w j / (1 - w i)) • a j)
⊢ ∀ i_1 ∈ t.erase i, a i_1 ∈ (convexHull 𝕜) s