Es seien M {\displaystyle {}M} und N {\displaystyle {}N} kommutative Monoide und sei K {\displaystyle {}K} ein Körper. In welcher Beziehung steht K − Spek ( K [ M × N ] ) {\displaystyle {}K\!\!-\!\operatorname {Spek} \,{\left(K[M\times N]\right)}} zu K − Spek ( K [ M ] ) {\displaystyle {}K\!\!-\!\operatorname {Spek} \,{\left(K[M]\right)}} und K − Spek ( K [ N ] ) {\displaystyle {}K\!\!-\!\operatorname {Spek} \,{\left(K[N]\right)}} ?
![{\displaystyle {}K\!\!-\!\operatorname {Spek} \,{\left(K[M\times N]\right)}}](https://wikimedia.org/api/rest_v1/media/math/render/svg/718d93b8d2e849ad6909cc09d8cfb4e2632a5912)
![{\displaystyle {}K\!\!-\!\operatorname {Spek} \,{\left(K[M]\right)}}](https://wikimedia.org/api/rest_v1/media/math/render/svg/209bd1a79aced03c543cb1c210d1e9f7c7c65216)
![{\displaystyle {}K\!\!-\!\operatorname {Spek} \,{\left(K[N]\right)}}](https://wikimedia.org/api/rest_v1/media/math/render/svg/a6985f1b9527054df2bd7ab61d9e601b27cb8807)