case h_nil
α : Type u_1
β : Type ?u.19015
n : ℕ
inst✝ : DecidableEq α
a : α
⊢ Finset.card (filter (fun i => a = Vector.get Vector.nil i) univ) = List.count a (Vector.toList Vector.nil)

case h_cons
α : Type u_1
β : Type ?u.19015
n✝ : ℕ
inst✝ : DecidableEq α
a : α
n : ℕ
x : α
xs : Vector α n
hxs : Finset.card (filter (fun i => a = Vector.get xs i) univ) = List.count a (Vector.toList xs)
⊢ Finset.card (filter (fun i => a = Vector.get (x ::ᵥ xs) i) univ) = List.count a (Vector.toList (x ::ᵥ xs))
α : Type u_1
β : Type ?u.19015
n : ℕ
inst✝ : DecidableEq α
a : α
v : Vector α n
⊢ Finset.card (filter (fun i => a = Vector.get v i) univ) = List.count a (Vector.toList v)
induction' v using Vector.inductionOn with n x xs hxs
no goals
case h_nil
α : Type u_1
β : Type ?u.19015
n : ℕ
inst✝ : DecidableEq α
a : α
⊢ Finset.card (filter (fun i => a = Vector.get Vector.nil i) univ) = List.count a (Vector.toList Vector.nil)
simp
no goals
case h_cons
α : Type u_1
β : Type ?u.19015
n✝ : ℕ
inst✝ : DecidableEq α
a : α
n : ℕ
x : α
xs : Vector α n
hxs : Finset.card (filter (fun i => a = Vector.get xs i) univ) = List.count a (Vector.toList xs)
⊢ Finset.card (filter (fun i => a = Vector.get (x ::ᵥ xs) i) univ) = List.count a (Vector.toList (x ::ᵥ xs))
simp_rw [card_filter_univ_succ', Vector.get_cons_zero, Vector.toList_cons, Function.comp,
  Vector.get_cons_succ, hxs, List.count_cons', add_comm (ite (a = x) 1 0)]