Chinese Remainder Theorem
For ideals
Theorem. If $I_1,\ddots,I_k$ are pairwise coprime ideals, then
- $I_1\cap\cdots\cap I_k=I_1\cdot \dots \cdot I_k$
- $\phi:A\to\prod_i A/I_i$ is surjective
Theorem. If $I_1,\ddots,I_k$ are pairwise coprime ideals, then