fact: Fixpoint subst_map_expr (t : map_expr) (v v' : term) : map_expr := match t with | Empty => Empty | Add x y f m => Add (subst_term x v v') (subst_term y v v') (subst_term f v v') (subst_map_expr m v v') end.
imports: Coq.NArith.NArith Coq.FSets.FMaps Coq.micromega.Lia Category.Lib Category.Lib.FMapExt