is a polynomial ring, then the coefficient ring is the base ring from which the coefficients are drawn. If R
is constructed from a polynomial ring as a quotient ring or a fraction ring or a sequence of such operations, then the original coefficient ring is returned.
i1 : coefficientRing(ZZ/101[a][b])
o1 = ---[a]
o1 : PolynomialRing
i2 : ultimate(coefficientRing,ZZ/101[a][b])
o2 = ---
o2 : QuotientRing