Paper 3, Section II, G

Groups, Rings and Modules
Part IB, 2013

Let R=C[X,Y]R=\mathbb{C}[X, Y] be the polynomial ring in two variables over the complex numbers, and consider the principal ideal I=(X3Y2)I=\left(X^{3}-Y^{2}\right) of RR.

(i) Using the fact that RR is a UFD, show that II is a prime ideal of RR. [Hint: Elements in C[X,Y]\mathbb{C}[X, Y] are polynomials in YY with coefficients in C[X].]\mathbb{C}[X] .]

(ii) Show that II is not a maximal ideal of RR, and that it is contained in infinitely many distinct proper ideals in RR.