TmpChainCanonicalHom(R: RING, S: RING): RINGHOM

/**/ Use R ::= QQ[x,y];
/**/ RmodI := NewQuotientRing(R, ideal(x^2-1));

/**/ phi := TmpChainCanonicalHom(R, RmodI);
/**/ phi(x^3*y);
(x*y)