simp [header, addColumn, Schema.names]
η : Type u_η
dec_η : DecidableEq η
sch : Schema
τ : Type u
inst : DecidableEq τ
t : Table sch
c : η
vs : List (Option τ)
⊢ header (addColumn t c vs) = List.append (header t) [c]
η : Type u_η
dec_η : DecidableEq η
sch : Schema
τ : Type u
inst : DecidableEq τ
t : Table sch
c : η
vs : List (Option τ)
⊢ List.map Prod.fst (Schema.append sch [(c, τ)]) = List.map Prod.fst sch ++ [c]