fact: Definition Fnth := Build_PartFunct R _ (dom_wd R F) (fun x Hx => F x Hx[^]n) part_function_nth_strext.
imports: CoRN.tactics.CornTac CoRN.algebra.CSums CoRN.algebra.CAbMonoids Coq.Sorting.Permutation CoRN.util.SetoidPermutation Coq.Setoids.Setoid Coq.Classes.Morphisms Coq(Lia)