End Equiv_VS.
(** * Multiplication and inverse *)
(** Domination *)

Lemma domin_inv :
forall {T} {F : (T -> Prop) -> Prop} {FF : Filter F} (f g : T -> R),
F (fun x => g x <> 0) -> is_domin F f g ->
is_domin F (fun x => / g x) (fun x => / f x).