Section ordre.
Variable A : Set.
Variable f g : A -> nat.
Definition e_lexfg (a b : A) := f a > f b \/ f a = f b /\ g a > g b.
End ordre.
Notation lexfg := (e_lexfg _) (only parsing).
(* <Warning> : Syntax is discontinued *)

Theorem lexfg_systemSL :
forall (b : wsort) (M N : TS b),
e_systemSL _ M N -> e_lexfg _ (e_P1 b) (e_P2 b) M N.