Section ALMOST_RING.
Variable R : Type.
Variable (rO rI : R) (radd rmul rsub: R->R->R) (ropp : R -> R).
Variable req : R -> R -> Prop.
Notation "0" := rO.  Notation "1" := rI.
Infix "==" := req. Infix "+" := radd.  Infix "* " := rmul.

Lemma SRopp_mul_l : forall x y, -(x * y) == -x * y.