Canonical Qnat_addrPred := AddrPred Qnat_semiring_closed.
Canonical Qnat_mulrPred := MulrPred Qnat_semiring_closed.
Canonical Qnat_semiringPred := SemiringPred Qnat_semiring_closed.
End QnatPred.

Lemma rat_lrmorphism A B (f : A -> B) : rmorphism f -> lrmorphism f.
Canonical ratr_additive := Additive ratr_is_rmorphism.