Module Type OppCstNotation (Import A : NZAxiomsSig)(Import B : Opp A).
Notation "- 1" := (opp one).
Notation "- 2" := (opp two).
End OppCstNotation.
Module Type ZAxiomsMiniSig := NZOrdAxiomsSig <+ ZAxiom <+ Opp <+ IsOpp.
Module Type ZAxiomsMiniSig' := NZOrdAxiomsSig' <+ ZAxiom <+ Opp' <+ IsOpp
<+ OppCstNotation.
(** Other functions and their specifications *)
(** Absolute value *)
Module Type HasAbs(Import Z : ZAxiomsMiniSig').
Parameter Inline abs : t -> t.

Axiom abs_eq : forall n, 0<=n -> abs n == n.