intros as h
α : Type u_1
inst✝ : DecidableEq α
x : α
⊢ ∀ (as : List (α × Nat)), ¬x ∈ map Prod.fst as → map Prod.fst (incrCounts as x) = map Prod.fst as ++ [x]
α : Type u_1
inst✝ : DecidableEq α
x : α
as : List (α × Nat)
h : ¬x ∈ map Prod.fst as
⊢ map Prod.fst (incrCounts as x) = map Prod.fst as ++ [x]