Show that the ideal ( X , Y ) {\displaystyle {}(X,Y)} in the polynomial ring K [ X , Y ] {\displaystyle {}K[X,Y]} over a field K {\displaystyle {}K} is not a principal ideal.
![{\displaystyle {}K[X,Y]}](https://wikimedia.org/api/rest_v1/media/math/render/svg/2979004ad27b9ba60c428e400cbf04d9f0957730)
