no goals
M : Type ?u.23867
inst✝⁴ : Zero M
l : List M
inst✝³ : DecidablePred fun x => getD l x 0 ≠ 0
n : ℕ
R : Type u_1
inst✝² : AddZeroClass R
x : R
xs : List R
inst✝¹ : DecidablePred fun i => getD (xs ++ [x]) i 0 ≠ 0
inst✝ : DecidablePred fun i => getD xs i 0 ≠ 0
⊢ toFinsupp (xs ++ [x]) = toFinsupp xs + Finsupp.single (length xs) x
classical rw [toFinsupp_append, toFinsupp_singleton, Finsupp.embDomain_single,
  addLeftEmbedding_apply, add_zero]
no goals
M : Type ?u.23867
inst✝⁴ : Zero M
l : List M
inst✝³ : DecidablePred fun x => getD l x 0 ≠ 0
n : ℕ
R : Type u_1
inst✝² : AddZeroClass R
x : R
xs : List R
inst✝¹ : DecidablePred fun i => getD (xs ++ [x]) i 0 ≠ 0
inst✝ : DecidablePred fun i => getD xs i 0 ≠ 0
⊢ toFinsupp (xs ++ [x]) = toFinsupp xs + Finsupp.single (length xs) x
rw [toFinsupp_append, toFinsupp_singleton, Finsupp.embDomain_single,
addLeftEmbedding_apply, add_zero]