exact List.map_map_append cs aggs Prod.fst Sigma.fst Sigma.fst
η : Type u_η
dec_η : DecidableEq η
sch : Schema
t : Table sch
cs : List (CertifiedHeader sch)
inst : DecidableEq (Row (Schema.fromCHeaders cs))
aggs : List ((c' : Header) × (c : CertifiedHeader sch) × (List (Option c.fst.snd) → Option c'.snd))
⊢ List.map Prod.fst (List.append (List.map Sigma.fst cs) (List.map (fun x => x.fst) aggs)) =
    List.append (List.map (fun x => x.fst.fst) cs) (List.map (fun x => x.fst.fst) aggs)
no goals