simp [Finset.sum_boole, Finset.filter_eq, hx]
case a.refine'_2.hw₂
𝕜 : Type u_1
E : Type u_2
ι : Type u_3
inst✝¹ : SeminormedAddCommGroup E
inst✝ : NormedSpace ℝ E
s t : Finset E
hs : AffineIndependent ℝ Subtype.val
x : E
hx : x ∈ s
hsnonempty : s.Nonempty
centroid_weights : ∑ i ∈ s, Finset.centroidWeights ℝ s i = 1
n : ℕ
⊢ (∑ i ∈ s, if x = i then 1 else 0) = 1
no goals