fact: Definition map_var {V W: Type} (f: V → W): Expr V → Expr W := fix F (e: Expr V): Expr W := match e with | Mult a b => Mult (F a) (F b) | Zero => Zero | Var v => Var (f v) end.
imports: Coq.Classes.Morphisms Coq.Program.Program Coq.Unicode.Utf8