Example of a setoid: Q

Setoid

Addition

It is associative and commutative.

Opposite


Lemma Qopp_wd : fun_wd (S1:=Q_as_CSetoid) (S2:=Q_as_CSetoid) Qopp.

Lemma Qopp_strext : fun_strext (S1:=Q_as_CSetoid) (S2:=Q_as_CSetoid) Qopp.

Definition Qopp_is_fun := Build_CSetoid_fun _ _ _ Qopp_strext.
Canonical Structure Qopp_is_fun.

Multiplication

It is associative and commutative.

Less-than