# coefficientRing -- get the coefficient ring

## Synopsis

• Usage:
coefficientRing R
• Inputs:
• Outputs:
• a ring, the coefficient ring of R

## Description

If R 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]) ZZ o1 = ---[a] 101 o1 : PolynomialRing i2 : ultimate(coefficientRing,ZZ/101[a][b]) ZZ o2 = --- 101 o2 : QuotientRing