fact: Definition ilist3_tl' {n} {As : Vector.t A (S n)} (il : ilist3 As) : ilist3 (Vector.tl As) := Vector.caseS (fun n As => ilist3 As -> ilist3 (Vector.tl As)) (fun a As m => ilist3_tl) As il.
imports: Coq.Lists.List Coq.Strings.String Coq.Arith.Arith Fiat.Common.ilist Fiat.Common