Definition Elt: Prop := Ecmp _ x y = Lt.Definition Egt: Prop := Ecmp _ x y = Gt.Definition Ele: Prop := Ecmp _ x y <> Gt.Definition Ege: Prop := Ecmp _ x y <> Lt.Definition Eltb: bool := match Ecmp _ x y with Lt => true | _ => false end.Definition Egtb: bool := match Ecmp _ x y with Gt => true | _ => false end.Definition Eleb: bool := match Ecmp _ x y with Gt => false | _ => true end.Definition Egeb: bool := match Ecmp _ x y with Lt => false | _ => true end.

Lemma Ecmp_inv_sym x y c: Ecmp e x y <> CompOpp c -> Ecmp e y x <> c.