Canonical dvdC_opprPred x := OpprPred (dvdC_zmod x).
Canonical dvdC_addrPred x := AddrPred (dvdC_zmod x).
Canonical dvdC_zmodPred x := ZmodPred (dvdC_zmod x).

Lemma eqCmod0_nat (e m : nat) : (m == 0 %[mod e])%C = (e %| m)%N.