Canonical dvdA_opprPred e := OpprPred (dvdA_zmod_closed e).
Canonical dvdA_addrPred e := AddrPred (dvdA_zmod_closed e).
Canonical dvdA_zmodPred e := ZmodPred (dvdA_zmod_closed e).
Definition eqAmod (e x y : Algebraics.divisor) := (e %| x - y)%A.
Notation "x == y %[mod e ]" := (eqAmod e x y) : algC_scope.
Notation "x != y %[mod e ]" := (~~ (eqAmod e x y)) : algC_scope.

Lemma eqAmod_rat :
{in Crat & &, forall e m n, (m == n %[mod e])%A = (m == n %[mod e])%C}.